If there is a common theme for discovery posts here, it is for the genera Metacoceras and Petalodus. In the past, I’ve numbered each specimen using roman numerals. As I’ve gained specimens, I may continue the sub numbering but will make fewer individual posts about particular specimens. Two new specimens were found and added to the catalog over the past 30 days. The first is CG-0193, a tooth from the Brush Creek limestone that was thought to be missing a crown. The second is CG-0191, a new find from the Pine Creek limestone that helps disprove a personal theory I had about teeth from that horizon.

Also to note, the catalog identification numbers are chronologically out of order. I actually found CG-0193 first.

The Tooth With No Crown, or so I Thought

The specimen CG-0193 was found in Guffy Run while breaking apart a large boulder. I had found a specimen very close by last year (CG-0045), so it wasn’t a surprise to find a second tooth. When I found it, I thought that the crown was missing and that I had just recovered the distal crown tongue and a portion of the root. I first separated the tooth from a larger rock piece using a cutting wheel. Next, I set the specimen aside and determined that I could catalog it later.

Specimen CG-0193, Petalodus ohioensis.
CG-0193, Petalodus ohioensis. Fragment in left side of the photo was covering the specimen.

To my surprise, when I sat down to try to clean it up with an air scribe, the cleavage plane created by the tooth blade caused it to crack and jump out of the rock. The crown is now broken in half, with each piece adhering to a piece of rock. The specimen was much too fragile to work on with a vibrating tool after this, so for now I’ve decided to leave it be. The tooth is well formed, however, it’s missing most of the light gray/sliver surface area that is common for these teeth.

I plan on measuring the crown and perhaps trying to extract the tooth with more gentle methods in the future.

A Second Petalodus from the Pine Creek Limestone

While collecting limestone boulders in a Pine Creek limestone rockfall area, I was splitting boulders to do some pre-exploration. This also helps to lighten them, as I do a detailed examination on them at home. When splitting a smaller rock, the first split revealed a nice tooth crown. I searched for the missing corner, but it must have flown from the rock as I struck it.

The crown is very well-formed, with a clear distal crown tongue. When removing the tooth from the remaining matrix, two corners broke off. I glued them back on using Paraloid B-72, but this shows how fragile these crowns can be. I’ve tried not to overuse vibrating tools such as air scribes to clean teeth up, as they can do more damage than good.

Petalodus ohioensis, labial view.
CG-0191, Petalodus ohioensis, labial view.
Petalodus ohioensis, lingual view.
CG-0191, Petalodus ohioensis, lingual view.

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