Wyoming Dinosaur Ranch Blog

Geologic Column
By Frank Bliss

Folks are always telling me they have found some really cool “dinosaur eggs”.  I tell them they are probably not dinosaur eggs.  These rounded, spherical or elongated rocks that are often rusty red or yellow in color often fall out of sandstone outcrops.  These objects also often take on the persona of a cannon ball to the non-geologists out there.  Heck, they are heavy, round, redish and look like the right caliber for an 8 pounder. There is a simple (sort of) explanation.

These fairly common and certainly very interesting objects are called Concretions.  They are not man made and are not reptilian in origin either.  They are, in fact, naturally made by a somewhat complex series of events concluded with a simple process of cementation.  The following process is necessary for their formation.

Please bear with me here and use your minds eye.  Try to think of a thick bed of uniform sandstone as a 3 dimensional fabric (like a finely woven cloth but in three not two dimensions).  This 3 dimensional fabric allows water to flow freely through the holes between the sand grains.  A uniform fabric allows water to flow smoothly without obstruction unless a fragment of something other than sand (fossil, twig, root, rock, etc) disrupts a smooth passage of water.  Moving water (like in pipes in your house) creates an electrical field which in a uniform flow is (guess what) uniform.  Any disturbance in the water flow creates a disturbance in the electrical field which causes an “electric potential gradient”.  (don’t let that term scare you!)   An “electric potential gradient” means that the disturbed area might be more electrically positive (or negative) than the rest of the sand body.  This causes charged dissolved minerals in the water (ions) to be attracted to that area. These minerals that are attracted to that charged area literally accumulate there and cement the sand grains together like concrete (remember the term concretion!).

In other words, minerals in water flowing through the sand selectively cements together sand grains around a nucleus.  This process generally leads to very spherical, often concentric growths. Adjacent spheres may even grow together or an odd shaped nucleus can give very unusual final forms.  I think they are neat enough to take home when they are small enough to carry.  I have seen them the size of a small car and often they weigh many tons.

Over the years, I have collected a nice assortment of sizes, shapes, and types of cemented concretions which mostly reside in my gardens.  The composition of the cement varies greatly and includes: pyrite, marcasite, hematite, calcite, halite, dolomite and various silica minerals.  The iron cements are the most common around here though. Some rare concretions may even have very nice fossils (nucleous) within. Fortunately for us, Powder River County has more than it’s fair share of these nifty natural objects. Now you know they are not eggs or old cannon balls.  I don’t know too much about cannon balls but I’ll cover dinosaur eggs in a later geologic column.
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A little rock appetizer with that salad?

On a “global warming”  60 degree day this January, I was out working on a fence line less that 200 yards from my house.  I habitually scan grass less areas of ground looking for indian artifacts or traces of dinosaur fossil material.  (Though I need glasses for every other distance, I see perfectly at 6 feet to the ground.) I spied a nicely rounded black cherty pebble about 3/4 of an inch long with a slight polish.  I immediately dropped what I was doing and got on my knees to closely examine the area.  Deftly avoiding all but the aroma of the freshly derived bovine land mine nearby, I started picking up more of these pebbles right off the surface of an area about 2 yards on a side.  When I was done, I had a pretty full handful of small slightly polished pebbles made of various material and all nicely rounded.  I was excited.

If you remember nothing from the Geologic Column, remember this.  ”Always look for things that are out of place when looking for collectable things in nature”. Consistantly, up in this sandstone country, cherty/quartitic pebbles are not common at all and are infact rare.  In stream valleys such as the Powder River Valley, they are very common but not on my highland ranch.  Since they do not outcrop naturally here then any occurrence of them must be treated as a discovery so some kind.  Additionally, they were out on cattle land away from driveway or path, they were all of similar size, variously rounded, smooth and semi polished. I concluded they were not county crushed gravel falling off a muddy ranch truck.  Indians did not bring them in because they were too small to make into any effective tool. Where did they come from?

I have given you several clues.

Answer:  Vegetarian dinosaurs ate lots of roughage and needed help to break down the woody pulp in the bellies.  To facilitate this, they often ate gravel which tumbled around in their gut along with the roughage and aided their digestion.  (Chickens do the same thing today to fill their gizzard with pebbles.) These dinosaur gizzard stones are called gastroliths.  They are very collectable by themselves and are fairly common in areas where the Cretaceous Hell Creek formation outcrops. Their source however may have been from hundreds of miles away where such stones naturally occur and they were all carried here by the critter that swallowed them  They are not actually fossils but are considered trace fossils (ichnofossils) by paleontologists. An ichnofossil is just an indication that an animal was there, not an actual fossilized part of biological material.  This type of structure might also be tracks, trails, tail drag marks, and fossil poop (to be covered in a later Geologic Column).

Gastroliths come in all sizes (as do dinosaurs).  I have even found 10 pound stones half the size of a volley ball in direct association with dinosaur bones on the surface.  Just imagine the size of a creature that would swallow a 10 pound rock to help digest food.  I also have found pea sized stones obviously used by smaller creatures for a digestive aid.  They come in a variety of material but are almost all quartzitic, silicic, or chalcedonic in composition.  In other words they are made of hard stuff.  The softer ones got ground down very quickly or dissolved by the stomach acid.  Gastroliths may have a calcium carbonate coating from ground water flowing over them or they may be iron stained brown by the same process.  They are almost all semi-polished as if from the rock tumbler sitting on a dusty shelf in your garage.  And they usually are not single isolated stones often occurring in numbers that would have partially filled a stomach some 65 million years ago.  If you find one, keep on looking.

Before there was Tums for your tummy, there were stones for your stomach.

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Petrification as literally translated from the Greek is “to change to stone”  In Greek mythology, the serpent haired Medusa was so ugly that one look turned the viewer into stone.  The many boulders of petrified wood that occur around the area weren’t changed by Medusa’s glare.  The often beautiful fossil wood often gets more than a casual glance from most collectors however. Tell me that you wouldn’t pick up a nice piece laying in the Powder River Valley if you could get it back home.  (By the way, any rock you pick up, belongs in reality, to the land owner!) Fossil wood chunks are really desirable collectables.  There are even entire forests of ancient trees that were preserved and are protected as national monuments. Fossil wood occurs in nearly every state of the union and in most countries of the world.

Petrified wood is commonly called wood opal.  The “opal” part is to signify the small amount of water that is mixed in with the silica dioxide (SiO2) that the fossil is composed of.  (Real Opal is SiO2 with some water between the atoms) This SiO2 siliceous material is the same basic stuff that quartz is made of but it is not crystalline like quartz is. I need to point out that other minerals can also replace the wood material.  Coach Hayes (who has a geology background too!) presented me last year with a beautiful piece of petrified wood for my teaching collection from a secret site in southwestern Powder River County. Unusually this specimen has the petrifying minerals being iron oxide (hematite) and gypsum (selenite). It is not hard like the silica replaced wood but is very impressive none the less. The softer material would never survive water transport and as such is quite rare and will only come out of the ground in place (insitu). I understand a whole log of the material remains insitu. Thanks Coach!

One common process that petrifies wood might go something like this.  An ancient forest became buried by sediments too quickly for the wood to decay in an oxygen environment.  The wood was removed from oxygen and thus bacterial action for many hundreds of years to many thousands of years. During this time, the wood was exposed to minerals that were dissolved in (ideally) hot, acid ground water.  This groundwater penetrated into the porous parts of the buried wood where the wood acted as a lattice work which was slowly replaced by the silica.  The acid softened the wood fibers, changing the acidity, which caused the silica to come out of the solution and replace the wood fibers atom by atom. The wood was literally dissolved away by the acid water which left silica in its place. Technically, petrification indicates that the entire object was completely replaced by mineral material.

It is important to note that the process of Permineralization is slightly different as some of the original material remains with only the pores being filled with silica. Some petrified wood can be up to 15 percent original wood material.  Voids in the wood are often filled with a geode like material. What ever the wood was replaced with originally may even be replaced again at a later date if the ground water chemistry changes. A sequence of events like wood to calcite to silica or any combination of the above is possible.

A myriad of color combinations is probable because of the various decay rates of the different parts of the tree rings and branches. This occurs along with the mineral content in fluids changing in composition/proportion over a broad time frame. Impurities (mineral salts) such as calcium carbonate (calcite), pyrite (fool’s gold), dolomite (magnesium rich calcite), iron and magnesium oxides all contribute to the various colors of red, yellow black and orange.  Thus, different compositions over time of the impurities results in different colors. The quality of the replacement can be exquisite preserving even microscopic detail of the original flora.

There have been some recent news stories you might have seen where a lab in Washington State has created a process to artificially create petrified wood under controlled condition albeit on a very small scale.  They might use the process to enable certain industrial uses but they won’t be cutting book ends for your fireplace mantle with them. Mother nature does it better in this case.

Keep your eyes on the ground and look at what you kick.  One, it might hurt, or two, it might be petrified wood. I have even found beautiful petrified pieces as gravel in driveways.

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Dinosaurs used to live here but you would be hard pressed to see any evidence of them.  As a group, they are mostly romanced by children but some of us never really grow up.  I spend a great deal of my spare time “climbing stairs” around the local hills looking for the evidence of their passing this way.  It helps me stay in shape as climbing around outcrops really gets the ticker racing.

In some places around Montana, dinosaur fossils lay about as so much detritus on the surface, As such, the remains are often ignored by the locals.  Around Powder River country, most of the clues that they left are very subtle.  There are not piles of fossil bone just laying about for the casual hiker to pick up and take home to lay around the garden. In badland country, soil moves quickly away such that any fossil is quickly exposed. The grass here however, has effectively slowed the rate of soil removal and subsequent bone exposure.  Fossil bone material usually decays into dust when acted upon for long periods of time by soil acids. So grass by it’s nature prevents fossils from surviving, being exposed and finally discovered.  Because of this, we are not known as the Dinosaur capital of the world.

We could be one of the dinosaur hot spots of the globe if everyone knew what to look for and where to look.  Fossils are everywhere in Powder River County, they are just tricky to find. VERY GENERALLY, it can be said that any rocks to the west of highway 59 are younger than the dinosaurs but rocks, just to the east are about right.  Three things control the occurrence of dinosaur fossils: the thickness of the Hell Creek Formation (Dinosaur fossil bearing) the elevation of the topography, and the regional dip of the rocks.    Certainly gullies expose bedrock and they are a likely place for fossils to be found.  (Watch out for other things that hang out in gullies too like bulls, rattlesnakes and really big kitties).  The Hell Creek Formation may be up to 700 feet thick around here so there is a variable swatch of exposure on the map that runs from Hammond all the way down to Newcastle Wyoming (Hell Creek Formation is called Lance Formation in Wyoming).  This band ranges up to 14 miles wide at times.

Too high, or too low, too far east or too far west and you are out of luck if it is dinosaurs you seek.  To the east of the Hell Creek formations exposure will be marine fossils with only rare marine dinosaurs possible. To the west, mammal fossils along with crocodiles, turtles and various other more modern types are abundant but no dinosaur remains are present.  The trick is to keep your eyes to the ground, know where you are and be aware of things that don’t belong. Rock outcrops are common everywhere but fossils may only be on the surface on some of them.  I often use the “look” of a sand bed to determine where to dig. This feeling is developed by many years of hunting fossils.

Things to look for include, shiny black enamel gar pike fish scales (easy to see and a sign that says dig here), sand with muddy pebbles mixed in (often not exposed on the surface but will be just under a thin weathered coat of sand) which you have to rake away to see the pebbles.  This sand/muddy pebble mix is the best sediment to find a large variety of dinosaur fossil material.  This material was laid down in the center of a river during a flood event which washed the dried mud off a mud flat (along with any piece of bone or teeth that was lying about).  This type of deposit is called a microsite because they usually don’t contain complete dinosaur remains but can contain almost anything else but usually has small fossils.  These may include: salamander, fish, turtle, frog, reptile, dinosaur, mammal, and alligator bone/teeth/claws/parts.

Remember that fossils belong to who owns the land.  That includes the federal or state governments.  It is illegal to take fossils from government lands.  Private lands can be searched with permission to access but make sure to discuss who owns what if you discover the tip of the tail of the complete T-Rex.  If you think you have important fossil remains on your ranch, I would be tickled to get involved but be warned that if you have something important, a museum or university will follow up with the collection.  You may get a big tax deductible donation, I will get a free education, and the institution will get a nice display to study and learn the past from.  A win, win, win situation.  More about dinosaurs later.

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Upper Cretaceous Dinosaurs are actually pretty uncommon in the world. The most common and most well known being the browsing Triceratops.   Triceratops was a giant of a fellow.  Much like the animal shown in Jurassic Park (the movie).  They were the cows of their time being herbivores in contrast to their carnivorous arch enemy Tyrannosaurus rex.  Every ecosystem needs a grazing animal to facilitate the energy conversion from sunlight to plant matter, from plant matter to meat, from meat to upper level carnivore.  The end of the Cretaceous period was no exception.  The amount of vegetation must have been staggering to behold.  Cycads, ginkos, deciduous trees of all kinds, numerous flowing plant were abundant but there was NO grass yet.  It hadn’t evolved by the time the dinosaurs died out at the end of the Cretaceous.  Triceratops were the cows of their day, but they didn’t eat grass like our cows do today.  Their diet consisted of any luckless leaf they could reach, their cobble filled stomach could grind up probably anything they could pass through their system.  They did have teeth but not front teeth, only rows of teeth along each side top and bottom.  The front of their jaws were terminated in a beak of material similar to a birds beak which effectively scissored off any thing they could get between the edges.  Anyone who has been bitten by a parrot can identify with that.

The Cretaceous version of Triceratops was well along their evolutionary ladder being bigger (more robust), and well defended with three large horns and a bony shield back over their necks.  Earlier animals were much smaller, less armored and poorly adapted to face the evolving predators that appeared late in the Cretaceous.  It was an arms race to the level that the “Cold War” never reached.  Predators got faster and bigger, prey got better defended and just plain harder to get.  Horns, armor, tails with clubs, and various other defensive weapons were developed by prey to defend their lives.  (The mammals just hid down in the weeds and tried not to be seen.) So what is dinosaur science really about?

Preserved Triceratops footprints can be upwards of  20 inches wide which illustrates a leg bigger than an african rhinoceros.  They were not rhinos though. Falling into the pit of modern analogy is useful but the pit is full of problems.  Comparing modern large animals with ancient dinosaurs will prevent an unbiased observation from occurring.  So such analogies are only useful to the public and are widely ignored in the scientific literature.  Remember that science is a detective story.  Observations of the fossils records provide insight to what went on in the past.  My favorite tidbit of outcrop wisdom is: “Things are what they actually are, not what they seem, or what you have been told they are.”  I try to make my students realize that the story told in the rocks is one that has many possibilities but only one right answer. Paleontology is the search for the way things actually are (were).

I am currently slowly digging out a Triceratops (named Doug) that has already provided 5 complete ribs, a dozen partial ribs , a lower left jaw, a dozen vertebra in large blocks, several isolated vertebra, and a beautiful partial horn.  Much more remains in the outcrop.  He is a fair sized animal with one of his big ribs only being 6 feet long.  What magnificent creatures they must have been.  It will take years to get him out of the hill side he is in since he would probably dwarfs  a F350 Superduty pickup and his pelvis will weigh over a ton. Paleontology is the study of biological process over time.  The act of Paleontology is the practice of patience over time.

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Earth scientists study any aspect that warrants close attention. Young ambitious graduate students will study almost anything.  As a grad student, I looked in detail at a two foot thick bed of 400 million year old lagoonaly derived limestone that covered about 100 square miles of south eastern Indiana, others were doing different tasks their professors dutifully assigned them.  One of the least known and most maligned professions is paleoscatology.  The people that follow this field would be known commonly as folks who study fossil poop (called coprolites in the business) or just fossil scat. Some people study fossil species other study fossil feces.  OK, enough with the bad humor…

Regardless of the snickers out there, I remind you that information comes to the geologist in many ways.  While the actual fossilized poop is not technically a fossil but an inchofossil (not actually a part of the biological organism that was fossilized but a trace that it was there.) There is a lot of information in a fossil scat pile. Just like modern scatologists, paleoscatologists learn much about the diet of an animal that leaves these fairly common trace fossils around.  Carnivorous dinosaurs for instance, often have bone fragment that are identifiable within the scat.  This gives us a good idea of what certain species ate.  Some plant eaters have seed pods preserved within their leavings also giving up clues to diet and the surrounding fauna and flora of the area they were eating in.  This accumulated knowledge may even give information on the climate by knowing what plants were present by their seeds in fossil scat. We know which coprolites belonged to what animal because we often get them preserved along and inplace with articulated whole body fossils. I get a lot of turtle coprolites coming out of my fossil sites on my ranch.  Often the coprolite is the only indication that a particular species was around at the time the rock was deposited.

Other information gained might be the size and strength of the extruding alimentary canal (got that?), how far the drop to the ground (remember “the present is the key to the past”) and total loadsize.  Funny as these might be they give an idea of the configuration of soft parts of the contributing creatures anatomy not commonly preserved by fossilization, posture and amount of diet.  As you would suspect, really big dinosaurs had really big scat piles too.  Just watch the Jurassic Park episodes for this visual.  I am not sure what the starting wage of a paleoscatologist is but I will tell you that a doctors degree and at least 4 years of post graduate work is necessary for recognition in the field.

This is serious stuff here!  Ok, who laughed? Class, CLASS!

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Article: How to Approach Fossil Collecting and How Not to Get Shot at Doing So.
By Franklin E. Bliss
Bliss Ranch

So you want to collect dinosaur or other fossils and you are visiting an area
that might have federal/state/indian lands or even worse, the dreaded private land.
The following is a discussion of what it takes to have/gain access properly to get the
fossils out.

Common Sense Fossil Collecting Access

How you gain access to property that might have fossils depends on
where you are trying to get to.   The first rule is have a detailed map of
the area that has state/federal property marked as such.  Have yourself
located properly when you get there, and don’t hunt fossils if you
don’t know where you are. Don’t forget, sometimes to get somewhere, you
have to go across multiple properties. Sometimes even jumping across land corners
is considered trespassing.  Go figure.

Federal/State Lands:
Fossil Preservation act of 1996:
Federal Lands (which comprise a significant amount of area on the high
plains) are wonderful areas to collect fossils.  These are not to be
confused with Indian land to which you have NO access.  There is
however a very specific set of rules and regulations regarding
collection of fossils in general and scientifically unique fossils
specifically on federal property.  I am not  an attorney and as such
suggest that if you are going to seriously collect fossils on federal
lands that you reference the specific federal laws regarding this
activity. An internet search under the Fossil Preservation Act of 1996
will give you lots of night time reading.

Generally it is my opinion that as long as your collecting group is 10
or less in number, you are “reconnesance collecting” and don’t bring in
the bulldozers/explosives, you will be ok.  If you plan to disturb more
than two cubic meters of soil/rock, you better be contacting the
federal/state land manager for the area you are on.  Additionally you
better have a permit from the same manager to do so because the fines
and penalties are very significant for disregarding the law.
Generally, collecting fossils on the surface is not subject to
requiring you to inform the land manager. Remember that you are limited
to collecting surface specimens sitting ontop of weathered rock or
outcrop. You are also limited to using simple hand tools to remove
surface specimens. (You would be hard pressed to convince a federal
judge that a D4 Bulldozer is a hand tool.) The tools specifically
listed in the act are: hammers, chisles, prybars and rakes though I
suspect that the various itterations (like picks) are acceptable.

A federal manager may reserve a particular area and set it aside from
fossil collecting access.  Such an area might be already under study/be
a site and is being worked by a permitted educational institution.  He
is required by the act to publish this restriction in the federal
register.  The best action in our opinion, is to pick a likely area,
check with the local federal land manager and get a note from him that
it is OK to collect a particular spot.  It is always better to do your
homework. Under NO circumstances should you collect ontop of someone
elses digs.  You might and probably are breaking the law if you do. You
also might not want to collect in area that have endangered species
hanging about.  No quarrying activities are allowed on federal lands
without permit period.

State/Federal Parks/Preserves
Don’t collect there or even disturb the ground.  The penalties are
severe and you should expect special forces to come repelling over the
top of the cliff to arrest you.

Indian Lands:
Unless you are a reservation resident and have granted access by the
tribal elders in writing, don’t even consider it without a local
guide/friend with you at all times.

Private Lands:
The best plan with collecting private lands is to contact the land
owner and get permission in writing for access.  This permission note
should indicate who owns what if you find the million dollar fossil.
Tradition/law is that the fossils belong to the landowner/mineral
rights owner.   It is not unheard of to make a donation to the
landowners college fund to gain access. After 30 years of collecting
fossils, my general observation is, trespassers always seem to be
parking their car immediately next to the targets at a landowners
shooting range and the landowner is a terrible shot.  In other words,
don’t trespass unless you are willing to pay for the tow, replacing the
motor of your car and the price for breaking the laws both
federal/state and local. Some landowners can get downright nasty about
unannounced visitors.

Road side collecting:
Generally road side collecting is OK on smaller state highways and
county roads as long as you pull your vehicles far enough off the road
as to not cause a hazard.  This is as long as you are on the roads
right of way.  If you are off of the right of way, the above
considerations apply. The authorities patrolling interstate highways do
not allow cars to pullover and park on the right of way (to the fence)
period.  You might be able to get away with a warning if you collect
entrance and exit ramps.

Commercial Collecting:
The collection of fossils for sale is a whole subject by itself.  Some
people make a living collecting fossils commercially.  There is a huge
market in the United States for quality fossils and particularly for
dinosaur fossils. Individual specimens can sell for thousands of
dollars and the temptation is there to start a hobby and turn it to
money.  Generally, my advice is don’t.  First you have to obtain a
commercial permit to collect federal lands (not easy).  Second, any
rare fossil will have to be turned over to the government as it is
scientifically unique (good for us, bad for you). A few commercial
collectors (who have given the others a bad name) come in and destroy a
site just for a few fossils.  All the other information is lost to
science forever.  I personally think buying or selling very common
fossils is not a problem but the rare stuff should go to science.
Smuggling of fossils is another serious subject.  Some Chinese fossils
have made it to the american market.  The smugglers (if caught in
China) will be put to death.  Other countries deal with these
individuals in more interesting ways.

The statements above are general rules to follow and things to be aware
of.  This article is not all encompassing but hopefully will cover most
situations that you may find yourself in if you have the desire to hunt
fossils. Keep your eyes to the ground, watch out for the snakes and
good hunting.

Copyright 2004
Bliss Ranch
Frank Bliss
MS Biostratigraphy
Weston, Wyoming
frank@blissnet.com

The other day I went out to a pasture about as far away from my house that I can go on my own property to pick up an ATV left behind for some fencing activity the day before.  I hitched a ride to the site with Ray Williams and picked up the ATV around 8AM.  I figured while I was out there, I would check out a hill with just a little sandstone outcropping near the top that I had never been on before.  I knew it was in the right part of the geologic column for there to be dinosaur material possibly present.  Usually I just get exercise when I undertake such a stair climbing expedition up a large hill.  I knew this was different right away.

Upon starting up the hill, I noticed that there were a few light tan chunky dinosaur bone fragments (pretty small) in just the soil at the foot of the hill.  That is unusual I thought.  They always come down hill from above so I slowly worked my way back and forth, carefully noting where they were and were not.  That way, I was slowly working toward where they come out from above.  Even with this good sign of bone, typically all I get is a few fragments coming out of a layer or perhaps a single big bone weathered into an undoable puzzle by the elements.  The difference here is that the pieces instead of tapering off, kept increasing in number right up to the top of the hill.  On the top, I did a quick look around  and immediately dropped to my knees on a sandy slope strewn with the enameled black scales of the ancient alligator gar fish as well as some pretty nice pieces of dinosaur bone.  I immediately saw bone shafts, scales….a piece of fossil turtle shell, wait, a crocodile tooth, wow!!!! a curved sickle shaped tooth from a dromaeosaur (a 6 foot tall, really nightmarish chicken with teeth, a wishbone and sickle claws).  I continued to surface collect this spot for an hour and brought back numerous fossils including a dinosaur jaw fragment (no teeth), quite a few nice crocodile teeth, a dozen gastroliths (dinosaur gizzard stones) and a pocket full of other keeper dinosaur things.  I did note that there were a few big ant hills on the top though. I was on the site less than an hour.

Next day, I took my son Chris along with a screen sieve and a shovel to sample the work the ants did for me. For your future information, the proper process for sampling red ant hills is as follows, shovel ant mound material into sieve, sieve to suit, immediately bag all material in sieve in zip lock baggies ants and all, transfer material to wife’s favorite microwave safe covered dish, 120 seconds per 5 pounds of sediment on high will kill any imbedded ants.  (Run if wife finds out about the dish!) Do not, I repeat, do not try to examine material in the sieve on site after properly agitating ants. Formic acid is pretty irritating under the skin by the way.   I must have overslept the day the rest of the class was taught about Wyoming red ant hills in grad school.

The final result was absolutely astounding.  These little guys collected over a thousand little teeth for my enjoyment and scientific gratification. Go figure!   This mixture of teeth the ants gathers had hundreds of teeth from each of the following groups,  the Alligator Gar Pike fish, alligators/crocs, frog hips, vertebra from fish, amphibian jaw fragments, various baby dinosaurs (the ants can’t carry the big teeth which are still in the ground) and most importantly almost 100 Cretaceous fossil mammal teeth.  In three years of heavily collecting the Cretaceous Hell Creek Formation for dinosaur fossils, I have only accumulated perhaps 30 Cretaceous Mammal teeth specimens (VERY, VERY RARE THINGS!!). This new site it turns out, is a world class Cretaceous fossil mammal tooth site right here in Powder River County.  The academic paleontologists and the museum curators (mammal experts) will be down this summer and there will be papers turned out with these specimens.

I went back and spread a packet of wild rice about the top of the sampled hills to pay back the ants for their diligence and to help them survive the rebuilding of their mounds.  The rice grains looked like pupa and down the hole the soldiers dutifully carried their prize.  Hopefully they will have the mounds rebuilt by next year.

It may be difficult to write a column every week during the summer field season but finding amazing sites like this one makes it easier. Stay tuned

FB

Geologic Column
By Frank Bliss

Extinction of the Dinosaurs?

I am an active participant of  a 600 member strong internet mailing list consisting of experts from many countries in the many fields of Vertebrate Paleontology. The vertebrate part deals primarily only with animals that have backbones and the paleontology part means the study of ancient life. I am certainly one of the least educated members of the list and some of the discussions can get a bit hard to decipher even with a graduate degree in geology behind me.  One of hottest topics in the field these days is what killed the dinosaurs.

All the full time professionals have their own pet opinions and of course when you have 3 geologists in a room you have at least 4 professional opinions.  I of course have my own ideas that I will distill down as much as possible to save room.

For the last 18 years, the really popular story is that about 65 million years ago, a good sized impactor (about a 7 mile across asteroid or comet) smashed into the earth near the village of Chicxulub (pronounced Chik sil ub) in the Yucatan Peninsula of Mexico.  It was very close to the same time of this impact event that 75 percent of all the species on our planet went extinct. When this impact occurred, ejected rock from the crater enveloped the earth and rained back to the surface. Some scientists speculate the radiant heat from the huge amounts of suborbital rock reentering the atmosphere baked any animal that was not under ground, or under water at the time.  There were other effects similar to a nuclear winter where dust blocked out sunlight preventing photosynthesis for up to a year.  It might have been too dark to even see for up to 6 months.  Besides, the solid rocks thrown up, the carbonate/gypsum rich rocks at the impact site released sulfur dioxides in concentrations that produced very strong sulfuric acid rain and with the damage to the ozone layer adding to the insult by adding nitric acid rain to the mix.  This certainly defoliated vast areas of vegetation and changed the chemistry of waters by direct action and leaching poisonous metals from the ground. Massive forest fires destroyed the environment and cooled the climate even more. There is worldwide evidence for this event but this event alone does not explain all the rocks tell us.

An idea based on evidence from Alberta, Wyoming and Montana, is that dinosaur diversity was in decline for several million years before the end.  Around 7 million years before the disappearance of the dinosaurs, there were 30 families of dinosaurs but near the end of their reign, only 12 families remained. This decline may have been in response to gradual environmental changes combined with disease, competition or over specialization. Slow reproductive rates of large animals would also hinder their adaptability to change. The problem with this idea is that the fossil record is incomplete and most of the field work leading to this theory is localized to this region. It does not apply universally to world wide data.

My personal opinion is based on all of these ideas. It may well be that dinosaurs were in decline or were mostly killed by an asteroid impact. It makes more sense to me (and others) that animal populations (dinosaurs included) were slowly changing (dare I use the word evolve?) into more diverse creatures similar to modern birds and mammals.  The impact event in Mexico certainly added a huge stress to dinosaurians and upset their reproductive cycle which no doubt played a major part in the end result.  These factors operating in tandem would certainly result in a dramatic decrease in dinosaur population and the resultant increase in other forms.  These smaller, more diverse, more active and smarter competitors would easily fill in the ecological niches left empty by the declining numbers of larger species.  In effect, all the popular theories were right but the resulting extinction of large dinosaurs was the result of the combination of events not any particular one.

In my humble opinion, enjoy watching those little dinosaurs flying around in your back yard.

FB.