Bellvue Echinoderms

[ScarpedCliff]

Last November, my wife and I went collecting in northern Kentucky. We had visted a Richmondian site and were on our way back, when we happened to see a random road cut and decided to pull over and have a look. It was composed of blocky limestone rich with Vinlandostrophia ponderosa, and turned out to be part of the Bellvue Mbr. of the Grant Lake Fm. Within about 10-15 minutes, my wife found her first cyclocystoid, and I found my first edrioasteroid. As far as rarity, I'd say she definitely outdid me! These fossils got our hopes up for more, but the rest of the day plus a second trip with friends failed to find any additional echinoderms.

My wife's cyclocystoid measures about 12 mm in diameter. We don't know the species yet, but we are planning to meet with a paleontologist in Cincinnati soon to ID it.

My edrioasteroid is Isorophus cincinnatiensis, measures about 17 mm in diameter, and is upside down and partially broken. Jack Kallmeyer of the Dry Dredgers suggested it was likely attached to a clam during life, which then dissolved away after burial, leaving the underside exposed.

Edited February 6, 2016 by ScarpedCliff

[PA Fossil Finder]

Wow, great finds! Two rare echinoderms in one trip!

[FossilDAWG]

Those are two exception finds! Although Isorophus cincinnatiensis is probably the most "common" edrioasteroid in the area, the underside is rarely ever seen.

Don

[FossilDAWG]

It's funny how the frequency of occurrence of some fossils varies between localities. Cyclocystoids are exceptionally rare in the Cincinnatian rocks. However I found them to be a lot more easily found in the Ottawa Ontario Ordovician. Over the span of 7 years there I collected 9 specimens, including three slabs with two specimens each, which include three different genera.

Don

[abyssunder]

Nice finds! The cyclocystoid looks like Narrawayella cincinnatiensis.

[ScarpedCliff]

FossilDAWG, yes, I've heard they are fairly rare around here. I found another cyclocystoid in Ohio back in December, so I've been fortunate. Actually, to be entirely accurate, either my wife or I collected the rock with the second cyclocystoid back in October, but didn't notice the cyclocystoid until I was going through our collection in December. I could have discarded it!

It's only a partial ring, from the Preachersville Mbr. of the Drakes Fm., just below the Silurian.

abyssunder, thanks for the suggestion. One of the Dry Dredgers thought perhaps Narrawayella or Apycnodiscus. After we meet with the paleontologist, I'll try to remember to post what she thinks.

[ScarpedCliff]

Incidentally, I've heard that cyclocystoids may actually be more common than thought in at least some parts of the Cincinnatian series, but preserved too badly to identify in most cases. Bill Heimbrock discovered an impressive microfossil site in Kentucky that had incredibly high numbers of cyclocystoid plates, all disarticulated.

By the way, if you want some heavy reading on cyclocystoids, look at Smith and Paul's Revision of the Class Cyclocystoidea. If you have access through a university or something, you can get it here. Alternately, you can read it online here if you get a free JSTOR account.

Edited February 6, 2016 by ScarpedCliff