Backyard Trip

[Missourian]

As I was heading back, I found a stick that some rodent found tasty:

Along the way, I took a second and closer look at some Iola Formation exposed high above the creek-level Cement City:

The bedding was a bit jumbled in places due to slumping, but it seemed to be in its original spot. This piece of shaly crinoidal limestone confirms this as the Iola:

The large, partial brachiopod is Derbyia.

I climbed down to the Cement City Limestone to follow up on a couple details:

I checked to see what type of fossil made up the bioclastic 'cap rock':

Rather than the crinoid debris found at adjacent localities, this seemed to be composed of abraded shell fragments. It also seems to grade downward into the nodular layer.

I wrapped things up here and made a short drive over to the west side of the park to continue the search.

[Missourian]

I checked out a small side creek near the nice cut bank shown here http://www.thefossilforum.com/index.php/topic/25424-backyard-trip/page__view__findpost__p__286744 . There is a bit of Raytown Limestone near the mouth of the little stream, but it wasn't much to look at.

 

As I followed the small valley, I could see limestone exposed high up on both sides. The thin bedding is typical of the Argentine:

 

 

I didn't find any decent fossils here, so I continued on. Eventually, I reached the point where the creek cuts through the limestone:

 

 

I found this wonderful slab filled with productid brachiopods, but I couldn't take it with me:

 

 

Brachiopods aplenty:

 

 

As a bonus, I found this old farm implement sitting upon some older strata:

 

 

Amazingly, a tree had grown through the spokes of the wheel:

 

 

Ok, time to return to the car.

[Coco]

Hi,

On the 1st pic on #126 post, you have red fingers. I hope rodent wouldn't find them ... tasty

Coco

[Missourian]

On 2/24/2012 at 5:56 AM, Coco said:

Hi,

On the 1st pic on #126 post, you have red fingers. I hope rodent wouldn't find them ... tasty

Coco

 

Not likely. I'm too quick for them.... except for the squirrels.

[Missourian]

Along the side of our neighborhood lake are these rocks:

 

 

At first, I didn't give them much thought. They have no fossils to speak of, and they're hard to get to anyway. I wasn't even sure they weren't placed there when the reservoir was built. Lately, I figured out that these are an outcropping of Westerville Limestone.

 

Interestingly, on the other side of the lake, the waterline is level with the Quivira Shale:

 

 

This means the beds are dipping perhaps ten feet over a three hundred foot distance. It may not sound like a lot, but that is significant around here. The Winterset Limestone, which is exposed in the big creek below the dam (see http://www.thefossil...post__p__279541 ) should be dipping as well. Are there any more outcrops that will show more evidence of a structure? This calls for another recon.

 

From the dam, the big creek continues upstream to the north and east through a bunch of undeveloped land. I hadn't yet taken the time to check it out. So I put on my tattered jeans and old shoes, grabbed the camera, and went on my way.

 

Right off the bat, I spotted some Winterset Limestone:

 

 

This is just below the dam. It looks like it indeed is lower than the outcrop a couple hundred feet downstream, but it's possible that the upper beds have been removed by erosion. I'll have to take a closer look at a later time. For now, I continued on.

 

After a couple bends in the stream, I came across the upper part of a limestone bed:

 

 

These silicified gastropods mark it as Winterset:

 

 

So at least here the Winterset is lower. High above this in the woods is a 'rock garden' made up of Westerville:

 

 

Ok, moving on....

[Missourian]

As is typical in creeks around here, I walked a ways without seeing any more bedrock. I did find some loess with some striking bedding:

 

 

Up close, it seems to have a nodular texture:

 

 

After some more walking, I came across an exposure of limestone at the edge of the water:

 

 

This has the Lego-like appearance of the Westerville. So now it's down at the creek level? Hmmm.... Wait a minute. That is a chunk that had slid down the slope. If you look closely at the image, you may just be able to make out the outcrop of Westerville through the trees. I climbed up to take a closer look:

 

 

There were some outbuildings immediately above the limestone, so I left as soon as I snapped a few photos.

[Missourian]

I didn't walk too far before I saw this:

 

 

Wow. This is why I go to the trouble of trudging my way through the thicket. So what are these layers? Considering that the Westerville is high up on the hill above, these must be, from bottom to top, the Fontana Shale, Block Limestone and Wea Shale. I'll have to step over there to take a look.

 

After inspecting some of the loose boulders, I found this:

 

 

The hash dominated by Crurithyris and ammovertellids confirms this as the lower Wea.

 

Here are the beds again, with some scale:

 

 

The thicker limestone bed is the Block. The limestone above it is the hash bed within the Wea. The Fontana extends down to the waterline.

 

In one spot, a landslide had exposed several feet of the gray Wea:

 

 

Note the deer tracks running up the middle.

 

At the bottom of the slide is this jumble of blocks:

 

 

They look like a bunch of coffins. Oh look, the one on the right has shale on top of it. This could mean fossils:

 

 

Pretty nice. I could see a number of brachiopods, including Kozlowskia, Puntospirifer, Composita, Chonetinella and Crurithyris, as well as other types of fossils.

[Missourian]

Not to be completely outdone, the top of the Block Limestone contains a few Chonetinella:

 

 

As I looked downstream, I could see a large expanse of limestone exposed in the floor of the creek. This must be Winterset. I made my way down there to take a closer look:

 

 

Up close, I couldn't see any distinguishing features of the Winterset, but I did get this splendid view of the creek:

 

 

It was now time to turn around. The valley was opening up, which likely means no more bedrock. Also, I was getting close to some land that's posted.

 

As I returned, I spotted a couple more recent 'fossils'. Here is a stand of horsetails, a living fossil:

 

 

Those 'Calamites' are abrasive little suckers.

 

Lying in the grass was the remains of an unfortunate buck:

 

 

 

I also found an old Nova:

 

 

Would it be considered ancient or recent? 'Old Nova' is kind of oxymoronic, when you think about it. In any case, I'm not sure how they got it down here. At least I knew the way out.

[Missourian]

This fossil hash found in the lower Wea Shale near home isn't the best available:

 

 

Several miles to the south, in Jackson County, Missouri, the fossils stand out much better:

 

 

Cephalopods in the hash are rare but not unheard of. This is Metacoceras:

 

[Missourian]

Yesterday, I took the time to hunt a road cut close to home (see http://www.thefossil...post__p__281792 and http://www.thefossil...post__p__281934 ). The strata span from the Chanute Shale to the Argentine Limestone.

 

Thin-bedded sandstone within the Chanute was riddled with trace fossils. This is the top of the bed:

 

 

And this is the bottom:

 

 

I'm not sure if the same animals made the burrows on both sides.

 

After I collected a few of these plates, it was time to move up to the Raytown Limestone. I was trying to find a good specimen of Archaeolithophyllum. I didn't quite find what I was looking for, but I did find this:

 

 

The thin, horizontal holes are sediment-free voids beneath the algal blades. I'm not yet sure which side is up.

[Missourian]

Did you think I'd forget the strat chart for my latest creek adventure?

 

[Missourian]

I did forget to include the updated chart for the city park:

 

 

I didn't have room for the old tractor above the Argentine.

[Missourian]

The nature of the variable lithology of the Cement City Limestone is confusing, but it is starting to come together. I just needed to do a little follow-up on exposures in the neighborhood creek described here http://www.thefossilforum.com/index.php/topic/25424-backyard-trip/page__view__findpost__p__290932 .

 

When I took a sed-strat course back in the early 1990s, I drew up these charts showing the Cement City as it was exposed at the time:

 

 

 

The first chart is the mostly concreted-over outcrop shown before. I was particularly interested in the second, though, as it seems to show the nodular bed or something closely related, as well as the contact with the overlying Chanute Formation. So I set off again to see if I could relocate the beds.

 

I examined the creek bed where I remembered seeing the exposure. Besides a few scattered boulders in the banks, there was nothing to be found. As far as I know, the stuff could be buried elsewhere beneath the bank stabilization done by the City. Well that's too bad.

 

So I continued on to the little cuts I visited earlier. Maybe I can coax a few beds out of the leaf litter. Here is one of them, which is mostly the blue-olive beds:

 

 

Before I even reached those, I found a nice exposure that I missed last time:

 

 

Lets move in a little closer:

 

 

This section includes a portion of the blue-olive beds at the bottom, as well as some thicker layers I'd remembered seeing years ago where the concrete is now. One thing I noticed is that the thicker limestone beds seemed to be discontinuous:

 

 

These layers grade laterally from massive rock on the left to flaggy, crumbly stuff on the right. Could this be a variation of the nodular bed seen at other sites? Perhaps.

 

Also, the rock has the stalactite-like features similar to ones seen here http://www.thefossilforum.com/index.php/topic/25424-backyard-trip/page__view__findpost__p__302034 . I've thought these were burrows, but they very well could be solution cavities.

This rock is fossiliferous. I could see bits of Juresania in the mix.

 

About a foot up-section, above a 6-inch shale parting, is another bed of limestone:

 

 

The fossils are more pronounced in this layer. I pulled one chunk out from its place to get a better look at these Juresania:

 

 

The fossil content of these beds is very similar to that of the nodular stuff seen before.

 

The upper Cement City now makes a little more sense. Above the widespread blue-olive beds, there is what I've been calling the 'middle beds'. These tend to jut out a bit as a ledge, and vary in lithology, depending on the nature of the beds above.

 

The Cement City can be divided into three parts:

1. Lower ledge - Or 'base ledge'. This tight bundle of beds, ranging from 1 to 2 feet in thickness, is persistent across the 'greater neighborhood'.

2. Blue-olive beds - Typically a few feet thick, these nicely fossiliferous layers extend over the whole area. They are usually bluish or greenish gray, but they can be buff at times. Their distinctive appearance makes them easy to spot from afar.

3. Variable beds - The upper Cement City is too complex to define with the limited exposures around here. This portion appears to vary widely in thickness. The lithology includes fine-grained, medium-bedded limestone with variable shale partings, nodular limestone with clay matrix, crinoidal limestone, and a bioclastic 'cap rock'. As stated before, these seem to transition into each other, sometimes over short distances.

 

Interestingly, the coral Caninia torquia can be found in some of the variable beds, particularly in the lower part, but I've yet to see it in the lower ledge or the blue-olive beds. Perhaps the presence of this coral can aid in correlating the variable lithologies within the Cement City.

[Missourian]

Unsatisfied with my original description of the Winterset Limestone shown here http://www.thefossil...post__p__279541 , I took advantage of a warm afternoon to do some follow-up. If you recall, this outcropping is down low in the big creek just below the dam on the neighborhood lake. I walked down to the big creek and scrambled up the tributary to reach the big outcropping. The mouth of the little creek was caked with sticky mud due to the recent heavy rains, but it was worth it to see this again:

 

 

To give a sense of scale, the prominent bed at the bottom is about a foot thick. Here it is up close:

 

 

Recently, I've been pondering the nature of these micritic beds in the upper Winterset. Although they are usually barren, they can be spectacularly fossiliferous on occasion. Also interesting is how they tend to be discontinuous even over a few feet. Note how the bed appears to pinch out here:

 

 

At this spot, it has a concretionary appearance. That may in fact be what it is. Note how the surrounding shale seems to be wrapping around the irregular bed, and how it 'expands' out into the gaps in between. The limestone bed looks like it was squeezed into place, but I believe that it started out as calcareous concretions within the shale. The nodules started out in several places, and eventually coalesced into each other, forming the discontinuous beds. The cementation process was halted before the shale was compressed to its current thickness, which means this all happened relatively early on. I find this fascinating, as it provides a snapshot of the rock forming process. Here is a quick diagram:

 

 

These irregular beds can be found in the Winterset all across the Kansas City area. In some places, chert serves as cementation of these lenses.

 

Ok, back to the rock face:

 

 

I've began to doubt that the massive rock at the top of the section has cross beds. A little ways up the creek, I found a weathered exposure of the stuff:

 

 

What I thought were cross beds appear to be more of the 'concretionary' beds I noted before. As this is the top of the Winterset, I admired this waterfall before I made my way back to the big creek:

 

[Missourian]

In the adjacent cut bank in the big creek, I revisited these beds:

 

 

The thick bed is the same one we saw at the base of the previous exposure. One goal for today was to find some Cordaites leaves. After a bit of searching, I found this one:

 

 

A few marine fossils were found in these beds, including this Linoproductus:

 

 

and this myalinid:

 

 

I also noticed this outcropping of what I've been calling the 'Chondrites' bed:

 

 

The 'Chondrites' are actually molds of plant roots. A few were found here:

 

 

I'm not sure where the paleosol horizon is, but the Cordaites leaves found above may give a clue.

 

To summarize, the full section of the cut bank can be seen in this view:

 

 

There was a bit of shale showing below the blocky debris, but it isn't visible here.

[Missourian]

A little further downstream, I came across this outcrop:

 

 

Within it, I found these fusulinids:

 

 

(No, I don't have purple hands. )

 

As the little exposure was isolated and dissimilar to the Winterset, I figure it is a chunk of Westerville Limestone that had slid down the hill from above. I checked the Winterset rocks for fusulinids and came up empty.

 

I also found this richly fossiliferous rock:

 

 

Note the many echinoid spines. Unfortunately, there was no more of this hash to be found.

 

I also found a block from the lower Wea shale, as well as several unidentified blocks. Because of this, I had second thoughts about what I originally thought was an outcropping of the 'Chondrites' bed seen on the left here:

 

 

The boulders are not bedrock. They could be Winterset, but I think they slid from the Westerville above. The hummocky nature of the hillside above indicates a number of slumps and slides in the past.

[Missourian]

I then walked upstream to visit the cut bank directly below the lake dam:

 

 

Note the deer tracks in the sand.

 

The top-most portion of the Winterset is exposed here. Up close, some slabby beds are visible at the top:

 

 

while the beds at the same level just to the left are more massive:

 

 

Moss covered a portion of the rock near a small seep:

 

 

I didn't find any fossils here, but I did find this rather large clam shell:

 

 

Up on the hill are these old structures:

 

 

I couldn't tell what they were for, but they may be associated with the dam, or with the old quarry that the lake fills.

[Missourian]

An updated strat chart:

 

[Missourian]

The Winterset Limestone is full of surprises. Occasionally, it produces some spectacular fossils. I wanted to find more outcrops. There were two more spots to check.

 

For the first one, I followed the big creek downstream from the outcropping described in the previous post. A few months ago, I followed the creek on the flat north side. This time, though, I walked along the steep slope on the other side. To my surprise, it was an easy walk. I was expecting another thicket, but the only obstacle I encountered was some tree damage caused by a tornado a few years back. After climbing over, under and through the fallen trunks, I continued on my way. I eventually reached a small side creek that looked promising on the map. After following it most of the way, I found a modest exposure of the top of the Winterset:

 

 

I was hoping to find more of the lower part of the unit, but at least this was something.

 

A few days later, I made my way to another Winterset site that I had scouted out back in December. This is far downstream from the exposures shown at http://www.thefossil...post__p__290932 . I first revisited an exposure of the top-most beds:

 

 

Note the dip in the strata.

 

A couple bends downstream is this outcrop at the mouth of a small creek:

 

 

The massive layer on the bottom may correlate with the concretionary bed we saw earlier:

 

 

Cordaites leaves can be found in this bed:

 

 

As well as this gastropod. I have no idea what kind it is:

 

 

Other than a single Linoproductus, I didn't see any other fossils.

 

A little higher up are these two beds. Note the laminae in the one on top:

 

 

A loose block shows laminae penetrated with burrows:

 

 

These thin structures may be algal mats that formed on a tidal flat.

 

I followed the little side creek up until I encountered thick brush and rubbish tossed into the valley by nearby residents, but I didn't encounter any more outcrops. It seems that the remainder of the Winterset here had been removed by erosion, with glacial drift and loess deposited on top. Some of these loess bluffs are pretty high:

 

 

These caught my eye when I originally glimpsed the creek from the highway.

[Missourian]

I wanted to enjoy the nice weather today, so I checked out the woods behind the neighborhood lake. I scrambled through the spillway and down the steep slope:

 

 

(old pic)

 

I looked for fossils in the various boulders and cobbles scattered throughout the ravine. Most were Westerville and Cement City left over from dam construction. The laminae in this chunk of limestone caught my eye:

 

 

I had to take it home. When I trimmed off some excess rock, the piece split into two:

 

 

But when I looked at the break, I was greeted with this Ameura pygidium:

 

 

This is most likely from the Winterset Limestone.

[piranha]

But when I looked at the break, I was greeted with this Ameura pygidium:

In other words... a spectacular day

[Missourian]

On 3/17/2012 at 9:42 PM, piranha said:

In other words... a spectacular day

 

Indeed. With the laminae, it was like opening a book and turning to a page with a picture on it.

[Missourian]

After a few months of exploring the streams and ravines of my area, I've yet to check the creek upstream from my old home. Years ago, I found an outcropping that I figured was Raytown Limestone, but I didn't go up any further. A few days ago, I took advantage of the nice weather and set off to see what I could find.

 

There used to be a few, decent cut banks with sandstone and shale that were identified as the Chanute Formation, but they're now covered over for channel stabilization. All that's left is a bed here or there poking out from the jumbles of limestone blocks and old sidewalk slabs.

 

Oh, I pulled out some more Chanute trace fossils from my collection:

 

 

These probably were made by gastropods.

 

As I made my way past the improved section, I encountered bits of Chanute sandstone bedrock in the stream bed. They weren't much to look at, but they did help me identify the beds just up ahead. Flowing over the ledge of limestone is nice little waterfall:

 

 

This indeed is the Raytown. The two-foot section includes the Archaeolithophyllum-bearing wavy beds in the middle of the unit. Further up, the top of the limestone can be seen beneath the water:

 

 

Large, parallel gaps are filled with creek sediment. These formed along the preexisting joint pattern.

 

As I continued up the creek, I didn't see any more bedrock. I did, however, find an isolated block of limestone covered with some fascinating burrow casts:

 

 

 

These are Thalassinoides, which may have been formed by crustaceans. In this case, the bedding surface has been flipped over. I'm not sure which formation it came from. Most likely it was from the upper Kansas City Group, and was put into place by glaciers or construction activity.

 

The back sides of houses were starting to push right up to the edge of the creek, so I wasn't comfortable with going any further. I turned around and kept my eyes open for anything interesting as I made my way along the channel as I returned.

 

The extra attention paid off when I found my first artifact:

 

 

This was sitting on top of an exposure of old alluvium. The light blue-gray color first caught my eye. When I picked it up, I noticed the straight edge that had been worked and thought I had a broken spear point. However, the slightly concave surface on the other side gave me doubts. When I looked online, I discovered that I actually have a side scraper, which may have been used to clean hides. Judging by what was illustrated, it is a pretty nice one. The light, bluish material may be what is called 'Burlington Chert', which was collected from Missouri, Iowa, and Illinois. Perhaps some artifact enthusiasts on the forum may have some more info.

 

A couple days later, I drove up to a spot a little further upstream on the same creek to take a close look of an exposure of Argentine Limestone:

 

 

This has the wavy, thin to medium thickness beds that are typical of the unit:

 

 

Because there is always a deep pool of water below the exposure, I've never bothered to check it for fossils. I'd suspected that it produced these silicified Heliospongia that I had found several years ago in the creek gravel close to home:

 

 

Now, I'm not so sure. They could have come from soil derived from weathered Argentine from anywhere along the outcrop belt, or perhaps from another formation altogether. After exploring the outcrops of the area, I know these sponges can be found in the Spring Hill and Captain Creek Limestones as well as the Argentine, and glaciers could have carried them from who knows where.

[Bullsnake]

Congrats on the artifact! And, thanks for the continuing lesson.

[Missourian]

A stratigraphic chart for the Winterset exposures in post #144 above:

 

 

This time, I included the overlying Pleistocene loess and recent soil.