Backyard Trip

[Missourian]

Back at the west ramp, I climbed to the top of the ledge. The strata above the Captain Creek Limestone have been removed:

 

 

Peering over the edge, we can see the Captain Creek and the underlying Vilas Shale:

 

 

There are a number of fossils on top of the Captain Creek. Brachiopods and a few myalinid pelecypods can be found. Most impressive, though, are the large Heliospongia. Two can be seen here:

 

 

As I collected the sponges, I noticed that they were silicified. Just to be sure, I tested them by scratching a wine bottle. Soon after that, I gave them a muriatic acid bath. I am happy with the results:

 

 

From drab to exquisite:

 

 

Back to the ledge top....

 

There are some interesting mineral-filled cracks in the Captain Creek:

 

 

 

The next unit above would have been the Eudora Shale, but it had been scoured off. Scattered pieces of this black, platy shale could still be found:

 

 

And finally, this piece of Precambrian Sioux Quartzite indicates the presence of glacial drift. It started off from the area around Sioux Falls, South Dakota:

 

[Missourian]

A stratigraphic chart of the ramps and construction site:

 

 

Two more cyclothems are represented by the Plattsburg and Stanton Formations, where the Hickory Creek and Eudora mark maximum sea level.

[Kosmoceras]

An excellent report! Loved reading it! Thanks!

[Missourian]

For fun, I combined my stratigraphic charts into a master column representing about 200 feet of sedimentary rocks:

 

 

I included a curve of sea level at time of deposition, as interpreted on page 22 of this report (Warning: 7 MB PDF file):

http://www.kgs.ku.ed...5/B255partB.pdf

 

The lines mark points of maximum transgressions. Purple denotes black shales.

 

----------

 

Also, for what it's worth, I recently found a couple good exposures of the Wea Shale and Westerville Limestone in the area and was able to fill in the contact between the two.

[Missourian]

Unlike my previous walk through the woods, my latest jaunt was all rough and tumble.

 

A portion of the neighborhood lake fills what was once a quarry. The spillway was chopped into the slope next to where bedrock is exposed. Because of this, I figured there was a good chance of an exposure of Westerville Limestone and perhaps the underlying Wea shale as well. There was only one way to find out.

 

The dam is about fifty years old. Some beautiful vegetation has grown on its slope (taken back in September):

 

 

This wood and brush also will make for some miserable "walking" up ahead. At the other end of the dam, I followed the short spillway along a deer path. The upper part contains a nice little pond. Turtles play in there during the warmer months. Right now, the only things out were these strata:

 

 

The Cement City Limestone is above, and the Westerville is poking out above the water. The vegetation in between covers the Nellie Bly Formation and the Quivira Shale. I continued on.

 

I reached a point where the creek drops off a ledge of limestone. But then I remembered that I left my hammer back at the house (I had just removed it from my back pack because I "wouldn't need it"). So I walked all the way home to get it. Ok, now that I'm back with my 'scale', I can properly photo this complete eight-foot section of Westerville Limestone:

 

 

There is some reddish-brown chert at the top, which is in the same bed that is exposed on the nearby road (shown a few posts above):

 

 

After the obligatory slide down the mud into the creek water, I scrambled over and down to get below the limestone. Good grief, this was a horror show of obstacles. On a muddy, 20-foot, 50%-grade slope, there were trees with a thousand branches, a hideously tangled network of brush & saplings, thorny vines that resembled cactus, poison ivy vines, sharp and wobbly boulders, more vines, and dead branches everywhere. And through all this I carried a Nikon D70. At least there weren't rabid animals, barbed wire, or left-over quarry dynamite....

 

Anyway, back to the Westerville. Some of the wavy beds in the middle appeared to be made of crinoid debris. Here are a couple nice stems:

 

 

Sorry. That's the extent of the fossils here.

 

The little creek spills over the lowest beds of the limestone. The top of the Wea shale can be seen below:

 

 

Ironically, the ice present didn't cause me any trouble.

 

Further down into the mess, here is a second waterfall spilling across more Wea shale and a bunch of boulders:

 

 

After I scampered back up, I realized that I didn't have the lens cap. I checked all pockets, and, nothing. Ok, back down the slope and.... no cap anywhere to be seen.

 

Because I didn't have the cap on the camera, I was able to catch some geese in flight after I spooked them:

 

 

After I arrived home, I notice the cap was pressed into the wallet in my pocket.

[Missourian]

My backyard stratigraphic column is nearly complete. Only a few gaps remain. One is the lower part of the Wyandotte Formation. As I recall, a road cut a couple miles to the south exposes these layers. I must pay a visit.

 

This cut contains most of the Argentine, as well as the Quindaro Shale and the Frisbie Limestone beneath. The underlying Liberty Memorial Shale is covered:

 

 

The lowermost portion of the Wyandotte is conveniently contained within this chunk of strata:

 

 

In the Kansas City area, the Frisbie and Quindaro are difficult to distinguish from the Argentine.

 

The Quindaro varies from dark gray to black shale, representing the maximum sea depth within the Wyandotte cyclothem. Because the lower shale parting here is a fairly dark, neutral gray, I tentatively label it as the Quindaro.

 

Below that is the Frisbie. This single bed contains algal masses that resemble kettle-cooked potato chips, which is typical for transgressive limestones in these parts:

 

 

Above the Quindaro is a bed loaded with small sponges:

 

 

This marks the base of the Argentine. Here, some sponges stand out on a weathered surface:

 

 

As we move up through the Argentine, a series of limestone and shale beds are encountered. Eventually, it's all limestone:

 

 

The fossils here are predominantly phylloid algae:

 

 

Because I keep coming up dry in my backyard fossil hunts, I've included a couple rocks from the Argentine in a nearby suburb. This chunk is filled with brachiopods, as well as a nice Peripristis shark tooth:

 

 

A second piece boasts a Peripristis as well, along with a large Ameura trilobite head:

 

 

And finally, a stratigraphic chart:

 

[thair]

Realy neat report and fossils.

[Missourian]

I've been finding out that is doesn't hurt to walk along the little creeks in the area. I usually come across some nice outcroppings of rock, often in unexpected places. In one particular creek, I found more exposures of shale and limestone

 

In one cut bank, there is some limestone overlying some beautifully exposed shale:

 

 

Note the large blocks that have been undermined by the creek and left in place.

 

The shale has a nice bluish color near the water:

 

 

Higher up, it takes on an olive hue:

 

 

This transition from thick shale to simple limestone allows me to identify the strata as Wea Shale and Westerville Limestone.

 

At another exposure a bit upstream, the same sequence is encountered:

 

 

The Westerville and upper Wea up close:

 

 

There is phylloid algae present in the limestone. These seem to form little cups:

 

 

Behind this exposure, a small side creek runs up the hill. A third exposure of Westerville provides this setting for a little waterfall:

 

 

No water was flowing over the falls today.

 

Further up the little creek, I encountered more bedrock in the channel bottom. I'm not sure if it is more Westerville or the overlying Cement City Limestone:

 

[Missourian]

Interestingly, in all three full exposures of Westerville, the top half is missing. Originally, I thought the unit was thinner in the area. But less than a mile away, a full eight feet of strata is present, which is typical for the Westerville in the wider area. So what's going on?

 

Did the top part erode away? Probably. Was the rock broken down at the top, as would be expected beneath a soil? Not quite.

 

Present in the area are many large glacial erratics. This quartzite boulder was sitting in the creek bed just a bit upstream from the dry falls:

 

 

This tells me that it's quite possible that the glacial ice scoured off the upper Westerville along the weaker bedding planes in the middle of the unit, and then deposited some drift on top. Much later, the creek eroded through the glacial deposits and into the underlying Pennsylvanian strata.

 

In the vicinity, I've noticed that bedrock outcroppings tend to occur in the southern sides of streams, with few exceptions. Northern cut banks, where I've seen them, are usually made up of unconsolidated material, possibly loess. Also, topo maps reveal that the southern sides of creek valleys tend to be steeper than the much more gradual northern sides. I'm sure the advancement of the ice sheet from the north had something to do with these phenomena. It's as if the glacier preferentially plucked the bedrock from the north slopes and left deposits in its place.

[Missourian]

You may be asking: "More pictures of rock layers with few fossils?".... Well, I don't like to disappoint.

 

I've included some images of fossils of the Westerville from elsewhere.

 

In a certain spot in Jackson County, Missouri, the Westerville swells to about 20 feet in thickness where a shoal formed on the sea floor. This oolite and bioclastic limestone contains what can be called a megafauna of invertebrates. Large trilobites and mollusks of all kinds can be found, as well as coral, bryozoans, brachiopods, and crinoids.

 

An enrolled Ameura:

 

 

No, I'm not going to work on it anymore.

 

The nautiloid Domatoceras can reach over a foot in diameter:

 

 

This one doesn't include the living chamber.

 

The large gastropod Euconospira:

 

 

A pectinid pelecypod, my best ever:

 

 

I will post a more thorough Westerville thread in the future.

[piranha]

Amazing Ameura Missourian... Congrats!

[Missourian]

On 12/9/2011 at 4:08 PM, piranha said:

Amazing Ameura Missourian... Congrats!

 

Thanks.

 

I have two more Ameuras to show in the next post. They came from the Cement City Limestone in the creek just a stone's throw from home, found before the city covered the exposure over with concrete.

[lfsxdth]

A wonderful post!

[Wrangellian]

An enjoyable guide to your local strata! Wish I had someone who knew enough about my local geology to do a similar guide for here!

Nice pics and fossils. I hope you were able to pick up that chunk with ripple marks and trace fossils, that is a beautiful piece. I'm curious, if the Archaeolithophyllum is so abundant, is is possible to obtain a sample of it somehow?

[Missourian]

On 12/10/2011 at 5:23 AM, Wrangellian said:

I hope you were able to pick up that chunk with ripple marks and trace fossils, that is a beautiful piece. I'm curious, if the Archaeolithophyllum is so abundant, is is possible to obtain a sample of it somehow?

 

Thanks. Sometimes, the looking is as fun as the collecting. Sometimes....

 

The ripples are sitting next to me as I type.

 

Phylloid algae (red Archaeolithophyllum and green codiaceans) are in most of the limestones around here. The most 'showy' is the Archaeolithophyllum in the Raytown Limestone. To get a sample, just walk up to the rubble beneath an outcropping and pick your specimen. Or pry off a bigger chunk if you wish. I have a number of fresh and weathered samples. I would like to have some made into a sphere some day. It is even possible to get thin sections of the Archaeolithophyllum showing cellular structure, or the codiaceans showing layering. In most cases, though, this fine detail has been destroyed by diagenesis. I'd like to do it someday, but I'll have to search through the publications to find a locality where finely-detailed samples have been found.

 

By the way, the phylloid algae shown in the Westerville from my latest creek walk is probably of the green variety.

[Missourian]

On 12/10/2011 at 5:23 AM, Wrangellian said:

An enjoyable guide to your local strata! Wish I had someone who knew enough about my local geology to do a similar guide for here!

 

I had a glimpse of your island from the Inside Passage. I think it would take a little more footwork.

[Missourian]

The Cement City Limestone has been a source of frustration. In most places in KC, it is a massive ledge of thin to medium-bedded limestone. Closer to home, there are some calcareous shales in the middle that can make for some nice collecting.

 

The problem is that, most often, it seems to take steady stream erosion to really bring out the fossils. In road cuts and other 'dry' exposures, few fossils show up. This nice Caninia torquia coral, found at a road cut, is an exception to the rule:

 

 

There are only so many streams that cut through the Cement City, let alone leave it exposed in a cut bank. Years ago, there was a small, excellent exposure of the limestone in the creek near my childhood home. Here are a few specimens from that spot....

 

I found a number of Caninia at my creek spot. Ironically, though, I don't have any nice, whole specimens. The ones I did find were locked into the rock. A saw and a little polish reveal some fine internal structure:

 

 

These large horn corals are a handy stratigraphic marker for the Cement City. Caninia isn't found in any other layer in the metro area that I know of.

 

Some unidentified, flared rugose coral (edit: these may be Geyerophyllum.):

 

 

Syringopora, a.k.a. 'organ pipe' coral:

 

 

This is one of the few places I've seen this tabulate coral.

 

A cluster of the feather-like bryozoan Pinniretepora:

 

 

Kozlowskia, a small productid. This is the most common brachiopod in the layer:

 

 

Wellerella, an uncommon brachiopod:

 

 

Teguliferina, a rare, rudist-like brachiopod:

 

 

The trilobite Ameura. A whole trilobite head isn't often encountered:

 

 

Ameura again. There may be an enrolled trilobite in there:

 

 

Of course, it was only a matter of time until the city decided to dump a bunch of concrete over my favorite spot to "control erosion". Here's what's left of the cut bank, courtesy of Google Maps:

 

 

Um, guys.... a limestone ledge is pretty stable. You might want to tackle that loose soil over there instead, but I digress....

[Wrangellian]

I had a glimpse of your island from the Inside Passage. I think it would take a little more footwork.

That's for sure... It seems your Formations are all quite thin and multiple Fms can be exposed in one place - that's not so common here, even though the topography is complex.

[Auspex]

...Here are a few specimens from that spot....

Just because I'm a bird-nerd doesn't mean I love other fossils any less, and these have brightened my day!

Those Pinniretepora (feather-like bryozoans) are new to me, and quite wonderful

[Missourian]

On 12/10/2011 at 5:19 PM, Wrangellian said:

That's for sure... It seems your Formations are all quite thin and multiple Fms can be exposed in one place - that's not so common here, even though the topography is complex.

 

Yeah. I love our human-scale formations.

 

The formations out in the western part of the continent are ridiculous.... What you call formations, we call stages. Or periods.

[Wrangellian]

I guess we can't name our formations on such a detailed scale because our geology/topography is so tortured and it's almost impossible to trace layers for miles like you can.

Always something new to be learned here on the Forum!

[Missourian]

I was delighted to find the upper beds of the Winterset Limestone so close to home, but as you can imagine, more strata are lurking below it. As luck would have it, the big creek continues back into the woods along a north-facing escarpment. This area can be a real thicket in places, but the good possibility of finding outcroppings made the trudge worth it.

 

For a half mile or so, the banks are nothing more than mud and other loose stuff. When I reached the first cut bank into the slope, I encountered this spectacular, 30-40 foot exposure of loess. My backpack serves as scale:

 

 

All of the high banks on the north side of this stretch of creek appear to be loess as well.

 

Loess is glacially-derived, wind-blown silt that formed large drifts along the banks of the Missouri River. As the ice sheets moved across the continent, they picked up chunks of rock and ground much of it into particles ranging in size from clay to boulders. This sediment choked the river channel as it was carried along. As this was still a tundra environment at the time, there was no vegetation to protect the channel deposits from the fierce winds that could whip up on the barren landscape. While the gravel and sand continued to flow down-river, much of the silt and clay were blown out of the flood plain. The clay was carried away with the wind. The silt tended to pile up along the river banks. A little further out, it partially or wholly filled the pre-existing stream valleys.

 

Closer to the cut bank, we can make out some intriguing bluish-gray sediment:

 

 

It looks a lot like glacial till, but I didn't see any rocky inclusions. Note the old alluvial deposit below it.

 

Closer still, we can see some rusty stains in places. These very well could be the first stage of some concretion-forming process:

 

 

Can you see the raccoon paw prints?

 

Down at the next big cut bank, I spotted the top of the Bethany Falls Limestone sticking out of the water:

 

 

This unit lies below the Winterset. It is the regressive limestone within the Swope Formation. It is an economically important stratum in Kansas City. Besides providing raw material, its thick and sturdy nature provides a foundation for vast underground space used for warehousing, office space, and even paintball arenas.

 

Standing on the same exposure:

 

 

Stream erosion tends to strip off little slabs from the otherwise massive limestone. Unfortunately, few fossils are found in the Bethany Falls.

In the creek gravel nearby, I found several chunks of black, platy shale:

 

 

This is most likely the Stark Shale, which is the lowest member of the Dennis Formation, which includes the Winterset. Because of the size of the chunks, I figured that the shale must be outcropping somewhere close. I look around, but didn't find any.

 

Edit: The limestone at the water's edge could be lower Winterset, and the black shale found in the gravel could be Stark scoured from the creek bottom.

[Missourian]

Speaking of Winterset, is there any more of that limestone? The answer is down at the next cut bank. As I approached, I could make out some icicles on the slope in the distance. This told me that some kind of bedrock must be exposed there. When I reached the edge of the creek, I beheld a beautiful stretch of Winterset Limestone:

 

 

And over to the left, the thick-bedded lower Winterset is present as well:

 

 

I had to hop over and take a look. After scrambling up the incredibly treacherous slope, I was able to reach the massive bed:

 

 

I figured that this is what I've been calling the 'Chondrites bed'. At a number of other spots in the city, I found this rock perforated with burrows (or possibly roots). I've posted images in this thread:

http://www.thefossil...__fromsearch__1

 

When I got up close, I could see burrows here as well:

 

 

Another view of this fascinating bed:

 

 

Above the 'Chondrites bed', we can see a sequence of strata that is similar to what we've seen before. Note the bed with fine laminar layering:

 

 

Besides the Chondrites, I didn't find any fossils. I certainly will return to take another look.

 

A chart of the day's strata:

 

 

And finally, here are some "Calamites" that grow along the creek banks :

 

 

These are known as horsetails, scouring rush, and Equisetum.

[Kehbe]

Thanks Missourian! I was born and raised in western Wyandotte county, Ks. and now live in Raytown, Mo. and I have been climbing around on the different beds all over greater Kansas City, both sides of the state line, literally, since I was a kid, and still do today, but never really realized the diversity nor thought about the history and the make up of them, much less know the names and appearance of them. I consider myself fortunate to have a neighbor that is willing to tramp around and report his findings in a manner that an amatuer like me can understand. The strata charts are awesome and actually make sense to me. Thanks again for your efforts!

[Missourian]

I found a couple more pieces of the puzzle....

 

The big creek we've seen before passes through a city park about a mile from home. In the past, while walking along a jogging path, I noticed a waterfall over a rocky ledge:

 

 

Because this spot lies upstream and toward the general direction of the regional dip of the strata, I knew these rocks were higher up in the column. I figured they were the Raytown Limestone, and went on my way.

 

A little later, I returned to examine the rocks a little more closely. I found some more rocks further downstream that turned out to be Cement City Limestone. Because the waterfall rocks were higher up, I assumed they were sandstone within the Chanute Formation. Since I didn't spot any fossils within the Cement City, I left and forgot about the place.

 

Now that I have this mad urge to map out the strata in my area, I had to return to the park once more. I first closely examined the rock at the falls. I could see that the cap rock was made up of a fine fossil debris:

 

 

Just below it was this nodular limestone, which contained productid brachiopods:

 

 

Now I was perplexed. At the moment, this layer really seemed out of place.

 

I was getting pretty antsy anyway. The guy across the creek seemed to be pretty paranoid. There must have been a couple dozen no-trespassing signs all over the creek banks. I was almost tempted to walk onto the property just to count the signs....

 

Fortunately, because of sign saturation, I could easily tell where it was ok to proceed.

 

As I walked downstream, I came across a second bed of limestone below the nodular stuff. It formed a handy bench upon which to check the strata above:

 

 

This bed forms a second, shorter waterfall in the distance:

 

 

I found large chunks of sandstone along the way. I thought these might be from the overlying Chanute Formation, but I couldn't be sure they weren't something the glaciers dragged in from somewhere else.

 

Moving further along, we can now see the full extent of the Cement City and the bottom of the Chanute:

 

 

The thin-bedded limestones and shale comprise the bulk of the Cement City. The block of thin-bedded sandstone atop the cliff marks the base of the Chanute. The upper part of the Chanute was covered. Limestones of what may be the Iola Formation can be seen at the top of the hill.

 

Again, there is a convenient 'sidewalk' just above the water:

 

 

This ledge is probably the base of the Cement City.