Posts Tagged ‘bivalve’

Micro-Bivalve

January 1, 2011

A quick post from something on the hard drive…

Often, when inspecting corals(Cnindaria) or sponges(Porifera) that I have found in the Millersburg mb. of the Lexington, I find micro-fossils at the base of the colonies. It could be coincidental, but I’m starting to think that the micros were juveniles and that their progenitor placed the off spring in a habitat that favored survival, or the ones placed there were more likely to survive… which seems more plausible.

Anyway, here is a small bivalve that was collected from just such an environment.

A little closer

Since the common bivalves from the Millersburg are modiomorphids or ambonychiids, These are probably ambonychiids… probably Bysonnychia sp. juveniles.

More Seismites, and some fossils, too

April 13, 2010

North of Frankfort Ky, some outstanding outcrops of Ordovician rocks are exposed in road cuts along U.S. 27. The outcrops represent an accumulative sequence of sedimentation spanning several millions of years, and the fauna represented in the rocks are typical of Mid.-Late Ordovician shallow tropical seas-brachiopods, partial trilobites, bivalves, gastropods,… ect. All of the usual stuff.

I want to show you a few more photos of some seismites, but first, let me regress. I was in the area to work an outcrop that has been producing large numbers of crinoids, and other interesting oddities(like this and this). But, that morning I wasn’t having much luck finding anything. Though, as I was packing up to leave, I noticed some pinnate structure in a small stone.

Normally, I would pass on something so insignificant, but as this was a second species of crinoid at the outcrop, I picked it up and threw it in the backpack to further document the fauna at the site. When I started working this outcrop, I found a couple of pinnate arms from some kind of crinoid. Until this trip, I hadn’t seen any other crinoids other than the Reteocrinus sp. that are found in abundance in a small talus pile at the base of a small outcrop.

This is the insignificant pinnate structure after a little prep! I haven’t identified the critter yet, but I have an ideal.

A few other photos from the outcrop.

A big ol’ ambonychiid bivalve.

A hypostome from the trilobite Isotelus gigas. The critter that molted this would have been a monster… probably about 25cm!

Rynchonellids litter the ground at this outcrop.

A nice Hebertella frankfortensis.
anterior view

posterior of above

Strophomenids are nearly as common(Rafinesquina sp. in the lower center left).

A trepostomate bryozoan exposing the “tubes” of the zooecia.

A change in lithology from the Millersburg to the Tanglewood members of the Lexington Lm.

Cross bedding in the Tanglewood (a few centimeters from the contact).

On to the Owenton Rd.

A photo of the outcrop along the Owenton Rd. after turning from the bypass. I pulled this photo from Graham Young’s wonderful blog-Ancient Shore. He was in the region for the North American Paleontological Convention, last summer.

As the day was getting hot and humid, I didn’t spend much time at the outcrop looking for fauna, but I did find a few crinoid holdfasts(apparently, I have deleted them from my hard drive. I will re-photograph, and put them up in the future). But, I did save photos of the thick sequence of seismites.

close up of above