Random Fossil Post

I have lots of fossils from my younger collecting days that have no label or sparse information. Some are among my favorites but with little info they get relegated to Random Fossil Posts.

Two such samples are featured today with the first being this pair of slabs cut from, presumably, a stromatolite. Based on the preservation I'd say they are likely from the Wamsutter area of Wyoming on the Green River formation

Next up is this Gryphaea sp. shell. It is one of my favorites because it's in perfect condition, clean and is preserved with a light green calcite. My best guess is that it comes from England or France and is Jurassic in age. A search of Google for "Gryphaea" yields several examples labelled Gryphaea arcuata from the Lias (Lower Jurassic) of England.

Possible Hexactinellid sponge from the Keyser Formation

Another strange item that I've found in the Keyser formation are these fossilized "threads". I've found several instances of these fossils and they do not look like a geologic phenomena. When viewed normally they look almost like grass, leaves or wood but that is not possible as the Keyser formation is upper Silurian to lower Devonian in age and plants were not yet that developed.

A closer look reveals a definite fibrous structure and lack of layering. The "threads", as I call them, overlap and diverge from one another seemingly at random.

Another specimen with good examples. This has been polished a little by my Dremel tool to see if any other details emerge. I was starting to think they were fossilized algae or trace fossils.

I'm truly stumped by this one so I went to the Fossil Forum to see if anyone else recognized what they were. The general consensus is that they could be some root structures from a Hexactinellid sponge. There is a lack of good information on the fauna of the Keyser formation and so I'm still trying to determine if there are any known Hexactinellid sponges that have been found within it. I've found Stromatoporid sponges in the Keyser formation before and blogged about them Here and Here, but they don't have root structures; instead preferring to encrust and form mound like shapes. If anyone has any ideas please let me know.

Hindia sp. from the Louisville Limestone

When out collecting you often pick up a lot of stuff. Once you get home and clean your findings some of it turns out to not be as nice as you wanted or is not a fossil at all. And then sometimes you get a mystery like the specimen below.

This piece was collected from a mixed exposure of Middle Silurian aged Louisville Limestone and lower Devonian aged Jeffersonville Limestone near Louisville, KY. It was found loose within the heavily eroded red clay that often fills gaps within the limestone. The fact that it was loose and rounded made me think it could be a sponge or algae of some sort. Though it could just as easily be a rounded blob of quartz replaced limestone.

Thanks to the comment below, I looked at the specimen again and believe it to be an example of the sponge Hindia sp.