Jeff is fairly new to Bluff Country and fossil hunting, but a retired avid outdoorsman. He stopped by this morning to get some IDs on a number of fossils he had found. Jeff said he has only hunted three road cuts and been out perhaps 10 times.
This particular rock he found in the Prosser member of the Galena Formation. Here it is for scale:
I’m not real good at IDing trilobites, so I took some pictures and posted them in the ID Forum on thefossilforum.com (http://www.thefossilforum.com/index.php?/topic/54356-two-trilobites-with-my-guesses/) and Piranha was kind enough to take a look and ID them for me.
Isotelus species
I had guessed that correctly – look at the shape of the pygidium showing.
I had gone to the Midwestpaleo.com (side bar link) site and looked through all of the trilobites in the Galena and shale formations and guessed at a Ceraurus species trilobite for this one:
Basiliella barrandi out of the Prosser member of the Galena Formation, southeast Minnesota.
But Piranha did the same search but looked in the Platteville Formation and found it!
Basiliella barrandi
Here is Caleb’s Basiliella barrandi for comparison:
Basilliella barrandi from the Platteville Formation of northeast Iowa – Caleb Scheer.
