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Hi everyone, These were found in Bowmanville, ON, Canada, on the coast near Port Darlington. I would appreciate any help identifying these.

Found this one in Bowmanville (Mid Ordovician, Cobourg? Formation) last weekend. My best guess is Thaleops laurentiana cephalon but id like to have a better idea what it is before I attempt any more prep. Have not tried yet but probing with air abrasion looks like it will be difficult since the matrix is full of calcite or some other crystals. @Malcolmt @Kane @Northern Sharks

Quite a good showing at our biannual meet-up at Bowmanville's St Marys Cement quarry. I'm sure some of those TFF members who were there will post their finds in due course. I'll post my finds to kick it off, and hopefully others will join in. A big thanks to our intrepid trip leader, @Northern Sharks for organizing what seems to be growing in popularity among club-affiliated members near and far. It was a chilly one, for sure. At a high of about 5 C, at least it wasn't raining. Here's a group shot. Unless people want to be identified, I won't name names.

On an annual basis we get one day to collect in a pretty amazing quarry in Bowmanville Ontario. This year 2015 was no exception. My buddy Dave here on the forum had a pretty amazing day. I suspect many of us would kill for even one of the specimens he found that day. I just realized that I have never posted how his fossils turned out. Turns out he is popping by this weekend to pick them up before a mineral and fossil show up in Peterborough Ontario. Fossil Forum member Northern Sharks is a very active member of the club (Kawartha) that is holding the event. Here are Dave's finds for the day as found. They are all isotelus A pretty damaged isotelus .... but a large one A nice Double Another nice double A nice single

I just thought I would upload a picture of a very large doublure that I have been prepping from St. Mary's cement quarry in Bowmanville Ontario, Canada. This is a fairly well recognized site that has produced some amazing specimens over the years. Unfortunately for us collectors they only open it up to us one day per year, generally in October. There were at least 4 of us from the forum there this year. I did find a number of relatively complete isotelus that day but in hindsight I think this is likely the only piece that will stay in my own collection. (Pirahna, if you are reading this and have any good article on isotelus doublure, they would be greatly appreciated. I have been trying to find a good picture or diagram of a complete one from isotelus.) The picture is an incomplete doublure from an isotelus latus. (originally I had thought I. gigas but Kevin has pointed out what I think is a better identification) The doublure extends around the underside outer margin of the cephalon and is visible in the ventral view of a trilobite. In some trilobites the hypostome is attached to the doublure to provide structural stability to the feeding apparatus. What you can see is approximately 170 mm wide or about 7 inches, that's a Canadian quarter by the way which is basically the same size as a US one. Based on this I would estimate the minimum length of the trilo to be 12 inches perhaps even a bit bigger. You can see the terracing on the bottom surface quite clearly. The piece is not completely prepped at this point as I still need to clean up the tool marks. Prepping was via airscribe and dolomite air abrasion. Here is a link to a good paper on isotelus hypostomes http://www.academia.edu/213012/The_function_of_forks_Isotelus-type_hypostomes_and_trilobite_feeding