Morning Trip To Whiskey Bridge

[steve p.]

On the way to Ft. Worth to visit relatives, stopped at the famous Bryan location, for a morning hunt. (Only one fisherman there, no other hunters)

I must have gotten lucky because I chanced into a pocket of cone shells.

I pulled over 20 of them out. All had the lip broken, plus most had other damage also. They seemed to be in matrix that was fairly void of other kinds of fossils.

I wonder why so many cone shells would be in one place. I wonder if cone shells can live in close proximity? Or, would it be that water currents or similar forces would concentrate them?

I will post a pic later to show the lot.

Thanks

Steve.

[BobWill]

I've never been but I heard the best hunting is on the west side of the bridge but which side of the river do you hunt on. DPS went there last spring but I couldn't make it so thought of going on my own sometime.

[steve p.]

Bobwill,

I've only ever hunted on the west side. In the morning, that side is fairly shaded.

I would like to hear from anyone who has done any good on the other side!

Outside of the heat now, it is a really great place.

See my post here for more info.

I would like to hear from anyone who has hunted the east side of the river, as to where the fossil soil is.

Take it easy

steve.

[Oh-Man]

The west side is the cut bank and cuts into the formation while the west side is a depositional bank. Not to say that there aren't a few fossils over there, but the stone city formation is not there.

[steve p.]

The west side is the cut bank and cuts into the formation while the west side is a depositional bank. Not to say that there aren't a few fossils over there, but the stone city formation is not there.

Oh,

That makes a lot of sense.

On a previous trip, I walked the depositional side and just saw tall cliffs of sandy clay, I think.

Have you surveyed the cut bank side down stream of the digs? I can see a barbed wire fence coming nearly to the water's edge. It would be very nice to find an area that has a denser fossil shell matrix. I don't really know the legality of where it's legal to hunt also.

thanks

Steve.

[erose]

When the water is low and there isn't much sand on top of everything the side downstream is supposed to be good. I've been past the fence once just to scout and did not find it worth the effort. The beds dip in that direction so by heading downstream you are going up in the section. I've never heard anyone suggest the east side since it is all more modern sediments. But if you go east on 21 a mile you come to the Little Brazos and folks have told me there are fossils there as well. And supposedly a somewhat different mix. Let's see who else can fill in that info.

The cones do seem to often be in pockets. Sometimes currents sort stuff by size and they are some of the larger gastropods in that formation. I think modern cones are carnivorous and canabalistic so it is hard to imagine large concentrations of them. Again maybe someone can inform us.

[jkfoam]

When the water is low and there isn't much sand on top of everything the side downstream is supposed to be good. I've been past the fence once just to scout and did not find it worth the effort. The beds dip in that direction so by heading downstream you are going up in the section. I've never heard anyone suggest the east side since it is all more modern sediments. But if you go east on 21 a mile you come to the Little Brazos and folks have told me there are fossils there as well. And supposedly a somewhat different mix. Let's see who else can fill in that info.

The cones do seem to often be in pockets. Sometimes currents sort stuff by size and they are some of the larger gastropods in that formation. I think modern cones are carnivorous and canabalistic so it is hard to imagine large concentrations of them. Again maybe someone can inform us.

The Little Brazos is fossiliferous but it is not Stone City Formation. It is the Cook Mountain Formation. This location may not be as fossiliferous as the Whiskey Bridge but in my opinion it has a greater faunal diversity. Many people don't realize it but there are three formations exposed at the Whiskey Bridge site. At low water times and directly under the railroad and highway bridges is the Sparta Sand Formation, above that all the way to a limestone ledge is the Stone City Formation and from the limestone ledge to the top of the Bluff is the Cook Mountain Formation.

There are no fossils on the east bank of the Brazos River unless you go all the way down to the mouth of the Little Brazos River and then up into the Little Brazos River.

For a really good discussion of the stratigraphy of the Whiskey Bridge locality I recommend the following reference; "Stone City and Cook Mountain (Middle Eocene) Scaphopods From Southwest Texas" by Kenneth A. Hodgkinson, The University of Kansas Paleontological Institute, The University of Kansas Publications UKPCA 70 1-25 (1974). This publication is available on-line.

JKFoam

[MikeD]

The beds do dip down as you move east along the bank, eventually dipping into the water. You can hunt there when the water is low (like now). I have found some nice (and sometimes larger) specimens over there, but there is not as much area to hunt. There are fossils in the little Brazos, but I can't tell you much more than that. I've only hunted it once.

[steve p.]

The Little Brazos is fossiliferous but it is not Stone City Formation. It is the Cook Mountain Formation. This location may not be as fossiliferous as the Whiskey Bridge but in my opinion it has a greater faunal diversity. Many people don't realize it but there are three formations exposed at the Whiskey Bridge site. At low water times and directly under the railroad and highway bridges is the Sparta Sand Formation, above that all the way to a limestone ledge is the Stone City Formation and from the limestone ledge to the top of the Bluff is the Cook Mountain Formation.

There are no fossils on the east bank of the Brazos River unless you go all the way down to the mouth of the Little Brazos River and then up into the Little Brazos River.

For a really good discussion of the stratigraphy of the Whiskey Bridge locality I recommend the following reference; "Stone City and Cook Mountain (Middle Eocene) Scaphopods From Southwest Texas" by Kenneth A. Hodgkinson, The University of Kansas Paleontological Institute, The University of Kansas Publications UKPCA 70 1-25 (1974). This publication is available on-line.

JKFoam

Jk, I think I will hunt the Little Brazos River (LBR) soon. I like the idea of different stuff to look at. I've found but one shark tooth at Whiskey Bridge (WB) and look forward to finding more, maybe at LBR. More Vert fossils would be nice. I feel I have beat WB to death and have not been too lucky so far, though I have many of the most common stuff found there, including Dentalium fragments, and corals, possibly fish scales.

But back to WB. On this last trip, I thought I might attempt to understand the a foot or so of sediment that directly underlies the glauconite. I took two samples of that foot of sediment, one about 1 foot deep and one directly underlying the first fossils. I then put them under my scope at about 1x to 50x magnification. I thought that the sample composition might hint at the deposition environment. Plus, what cool stuff might be lurking there.

Sample 1 (0 foot deep, directly under the glauconite): overall seemed to be silt/clay sized particles. I noted a few large fragments of shell as the top portion of the sample met with the glauconite.

Sample 2 (1 foot deep beneath the glauconite): showed a fair amount of quartz sand, but mostly clay/silt sized particles. No evidence of life or fossils visible to me; pretty unamazing.

Note: I had discovered earlier the pellets of clam and worm excrement(?) that is characteristic of glauconite. Though, after doing the Hyrdogen peroxide treatment of mass quantities of glauconite, I realize it must be 99% silt/clay clasts.

So, my question is this: Why are fossils apparently absent or very very rare, in the two samples? Would you think that the two samples were laid down in the marine environment that laid the glauconite? Alternatively, might it have been just river transported sediment, laid before the salt water transgressed? Lost here!

Besides the above, what would be useful to me (and others I hope) would be a series of actual photographs at WB/LBR, illustrating and correlating the published geological columns to a real life example. (For me, the geological columns routinely published are great at home, until you get into the field, and then get lost.) I looked over that Kansas reference to WB and environs, but again, it is confusing. I might attempt to do a photographic study of maybe 30ft of WB strata assembled in a vertical panorama and labeled. That way maybe I can clarify things and educate myself (and poss. others) on the way.

Hope this is not too far off topic for TFF. During the last week without TFF, I was in severe withdrawals, though surfing the web pretty much proved the unique quality of this forum.

Steve.

Edited August 9, 2011 by steve p.

[steve p.]

Mike, JK, and erose,

You've made great contributions on this topic.

I appreciate it.

Steve.

Edited August 8, 2011 by steve p.

[jkfoam]

Steve,

I hate to tell you but the Little Brazos is no better than Whiskey Bridge when it comes to vert fossils.

JKFoam

[steve p.]

Steve,

I hate to tell you but the Little Brazos is no better than Whiskey Bridge when it comes to vert fossils.

JKFoam

Jk, you really know how to bring a guy down.

[steve p.]

<snipped>

The cones do seem to often be in pockets. Sometimes currents sort stuff by size and they are some of the larger gastropods in that formation. I think modern cones are carnivorous and canabalistic so it is hard to imagine large concentrations of them. Again maybe someone can inform us.

Yep, makes sense. Thanks. But then, I was curious to know if Conus is responsible for the tiny holes in the other clams I see. But, evidently Conus do not bore holes, they just spear. Seems it is Naticids who are responsible. I need to find out if Naticids are part of the commonly found Whiskey Bridge fossils. Google seems to be no help.

[Auspex]

Hope this is not too far off topic for TFF. During the last week without TFF, I was in severe withdrawals, though surfing the web pretty much proved the unique quality of this forum.

Steve.

This stratigraphic postulating is spot on-topic; 5 star with ginko leaf clusters! :Thumbs Up:

[steve p.]

This stratigraphic postulating is spot on-topic; 5 star with ginko leaf clusters! :Thumbs Up:

Ok, glad to hear and thanks for the great forum.

[MikeD]

Hope this is not too far off topic for TFF. During the last week without TFF, I was in severe withdrawals, though surfing the web pretty much proved the unique quality of this forum.

This is great stuff for the forum. Keep at it. dinodigger has a pretty good handle on the stratigraphy out there. I have stood there slack jawed in amazement as he pointed out to me what was going on in the various layers there. Maybe some of this will be in his paper. I'll have to touch base with him as I haven't seen him in a while.

[jkfoam]

Yep, makes sense. Thanks. But then, I was curious to know if Conus is responsible for the tiny holes in the other clams I see. But, evidently Conus do not bore holes, they just spear. Seems it is Naticids who are responsible. I need to find out if Naticids are part of the commonly found Whiskey Bridge fossils. Google seems to be no help.

Steve, Cone snails may not drill holes but many,many other snails do. You said that Naticids do drill holes and asked about the presence of Naticids at WB. Well, I can tell you that one of the most common snails at WB is Polinices aratus and that it is Family Naticidae. It has always amazed me that regardless of the size of the fossil at WB, even the smallest micros, something has drilled a hole in it and ate it. Living in the sea was not user friendly.

JKFoam

[steve p.]

Steve, Cone snails may not drill holes but many,many other snails do. You said that Naticids do drill holes and asked about the presence of Naticids at WB. Well, I can tell you that one of the most common snails at WB is Polinices aratus and that it is Family Naticidae. It has always amazed me that regardless of the size of the fossil at WB, even the smallest micros, something has drilled a hole in it and ate it. Living in the sea was not user friendly.

JKFoam

Jim,

Great. Polinices aratus is my first confirmed WB boring predator.

Micros with bore holes begs more questions for me, but that will be for another day.

Thanks very much.

Steve.