odd impressions ID help sought

I mistakenly sent my last inquiry to another forum. I`d like to know what caused these impressions. A different view than the other photo posted.

Looks to be some molds from fossil mollusks. Could be ammonite or a more moderm gastropod. Where are they from? Do you know the age of the rock as that would help ID the ancient culprit.

My first guess would have been water erosion like from a stream or river, but then I read Fossil Huntress's guess. I think she brings up a good thought. I haven't ruled out ancient animals. If she says ancient or modern mollusca or gastropod, then she might know more about that group than I do.


Sorry I couldn't be of much help....

I believe Huntress is on the right track. I live in Austin, Texas. There is plenty of aquatic fossils in this area. I thought the larger imprint may have been from one of the "Devil`s Toenails" that are everywhere just west of here. The smaller one though has a deep almost perfect roundness to the imprint. This entire region has a large chalk deposit that preserves many fossils and their traces. I will try taking some better pics and see if it helps any.

There is a paleo group in Austin that you may already be in contact with. They are pretty active collectors and could probably help quite a bit with IDing your finds. If you know the name of the creek or strata this is from I can look it up in the USGS.

Cheers!

I have not contacted anyone here about my collection. These rocks actually came from my backyard in Austin, Tx. Formations here are from cretaceous to paleocene. It is hard to make the camera see the same angles I do , but this is not normal erosion. I have also found many igneous stones as well as these metamorphic ones in question in my yard. My collection from this area ranges from tiny fossil shells to large ones and their impressions left as fossil traces. I also have a few large and very heavy slabs of seabed stones and a piece of petrified wood that is about 50 lbs. or so from south Texas. Here is another view of rocks.

wow! i would love to fossil hunt there i seen this site they find ammonites and even shark teeth. luck what else have you found there?

Tyler, this is a sample of what can be found just walking a creek bed for 15 minutes in the hills around here. I also have some that are not so common here. I`ll look into posting pics on gallery here instead of tying up the forum meant for questions.

JSpencer- Pretty nice fossil collection you got there! I'm impressed with the geology or your neighborhood!! Although, I wish I could help you. My expertise is in Theropod dinosaurs and not Invertebrates. I lack the geology training necessary anyway. Again, sorry.

No need for apologies Raptor. The person who knows it all is a liar! Austin used to be seabed so what we normally find are marine life fossils and their remains.

wow those are very cool! i know some of the there family names, black on hast to be a devils tonail and the other big swirly guys are snail shells aka gastropods. and the large clams are i think bachriopods im not 100% sure though about those. nice begginer collection though! ive never found a gastropod that big in MO. well good luck and happy hunting