Tuesday, August 30, 2011

Gibbithyris semiglobosa

Among the beautifully preserved fossils that are found within the Cretaceous (Turonian) aged chalk at Ault, France is the brachiopod Gibbithyris semiglobosa.

Thank you to my friend Gery for sending me this fossil. Below is a picture, that Gery took, of the cliffs near Ault and they are reminiscent of the cliffs of Dover in England and in fact may very well be the same age/formation.

Sunday, August 28, 2011

Coenites from Kentucky

Coenites is a fossil coral that existed from the Silurian thru the Devonian periods (443-359 mya). It's a fossil that I was always on the lookout for when fossil collecting as a kid here in Pennsylvania but I'd never found any specimens until a recent trip to Louisville, KY. While there my good friend Mike from Louisville Fossils took me to a spot that he and his cousin Kenny hunted. It was an exposure of Lousiville Limestone (Homerian to Gorstian stage) in which I found the below fossils. Note the criss-cross pattern of growth like a chain link fence that is typical of the genera.

This last piece has some Cladopora coral preserved alongside the Coenites. There has been some confusion between the two in the past as they have similar growth patterns. I think the difference is in the shape and pattern of the corallites or openings along the branches.

Friday, August 26, 2011

Calamites and Stigmaria from Hazard, KY

Calamites is a fossil genera that are common fossils in the Pennsylvanian swamp deposits. They often grew up to 30' high then although today the extant species are much smaller. The specimen below is part of a much larger fossil that represents the trunk of one of these ancient trees. It's from the coal mines near Hazard, KY.

Another fossil from Hazard is this Stigmaria root cast. Stigmaria is considered to be the roots of the scale trees like Lepidodendron or Sigillaria but early paleontologists didn't understand the anatomy of these fossils as they didn't find them articulated. It was only later as better specimens were found that the connection was made. In the specimen below each dimple would have had a smaller rootlet extending straight out like a bristle brush.

Up here in Pennsylvania I don't find these fossils as three dimensional casts. Instead they have been compressed and flattened by geologic processes. I'm very glad to have these two specimens as part of my collection and my thanks to Herb M. for giving them to me.

Wednesday, August 24, 2011

Micraster coranginum

Micraster coranginum is a large irregular urchin (echinoid) from the Cretaceous (Turonian) aged cliffs near Ault, France. Often these are referred to as Heart Urchins due to their shape when viewed from above.

Adapical surface (top)

Anterior (front)

Side profile

Posterior (Rear)

Adoral surface (underside or bottom)

My thanks go out to Gery for sending me this fossil.

Monday, August 22, 2011

Cyrtospirifer verneuilli

Large brachiopods are somewhat unusual with the largest fossil example being close to eight inches wide. Compared to Pelecypods, which have species that can grow up to five feet in diameter, they are typically a miniscule fauna. Thus when I come across exceptions to the rule, such as Cyrtospirifer verneuilli, I become fascinated. This species is from the Devonian (Fransian) rocks near Barvaux Sur Ourthe in Belgium. The specimen pictured below is about 3 inches wide along the hinge line.

Pedicle valve

Anterior (front)

Brachial valve

Posterior (rear)


Saturday, August 20, 2011

Beekite preserved fossils

Back in May of this year I found a hunk of Limestone that had some fossils in it which were preserved by quartz var Beekite. It came from the Centerfield formation which is Devonian (Givetian) in age and is from East Bethany, NY.

This is a view of the rock itself with the largest coral on the right.

There was also a brachiopod shell (Strophodonta demissa I believe)that showed the typical rounded "blooms" of Beekite.

I decided that I wanted to dissolve the limestone rock in acid and free the Beekite preserved fossils to see if they were 3-D. After a few hours the large coral was free and very well preserved.

At first I thought it was a Cystiphyllum americanum but the calice details are wrong. In a Cystiphyllum there should be blisters present instead of septa.

The Brachiopod shell wound up being a single valve but part was missing and had probably broken off before I found the rock.

To my surprise there were a few more corals that had been in the block. Two normal looking, small Heliophyllum.
Specimen #1

Specimen #2

As well as this coral with a very contorted history of growth.

And finally this small colony of Favosites sp.

On the side of the colony was yet another small horn coral.

Overall there were six fossils that were preserved by Beekite within that small block of limestone. The next time I head up to East Bethany I am going to look for more limestone with Beekite preserved fossils. Who know what else I may find once I dissolve the rock?

Thursday, August 18, 2011

Jurassic insects from China?

I was going through some boxes of mixed fossils that I'd bought years and years ago when I was not so organized or focused. I came across these two plates of fossil insects from China. Unfortunately the labels only indicate "Jurassic" and "China" so I have no real ID on them.

Plate #1 has a single insect that looks like a fly of some kind.

Plate #2 has two insects, one that is similar to the first plate and a second that looks like some kind of beetle.

The rock that composes the plates does not look the same as that which comes from the famous Jethol Biota of Liaoning China. If anyone has any ideas on the origin of the fossils or insect genera, please let me know.