This weekend I was able to get back to my Dundee Formation spot in Oxford County. The site is not quite perfect to permit full access yet, but in a few weeks (and early spring) will open up more of the rocks. It should be stated that these are brutally hard rocks that will shatter -- or the bones of the person who hammers these may shatter! This is why part of the excursion requires selecting the right rocks where natural forces have made them slightly more fissile for splitting. The fossils generally appear silicified, much akin to the Amherstburg Fm material I also collect from. Nothing amazing, but it was an interesting visit. I have already shown what the matrix is like in a post back in April, so I'll just show some of the things I picked up. Brachiopods are, by far, the most conspicuous and numerous fossils to be found in the platy layers, followed by abundant rostroconchs. Not only that, but the brachiopods could attain very plump and robust sizes as pictured above. There is an incredible diversity of them unmatched in most Devonian strata in Ontario. The brachiopod on the lower left is quite a looker, full detailed, free of matrix and with both valves. A calcified gastropod that looked sparkly in the sun at the upper left. And, of course, obligatory rostroconchs that I would put in my pocket if they came free of the matrix. I did keep one in matrix with a buddy brachiopod to function as an association piece should I donate a number of these to a museum. On to the trilobites. Most of the species in this horizon were encountered, including countless Pseudodechenella sp. parts I tend to pass over. I do make an exception for these Odontocephalus sp. given that they are very likely a new species, which means collecting as many samples as possible. They were not as numerous today, and there were some fragments of denticle cephalic margin I didn't bother collecting, as well as some pygidia that were too busted to be of much use. Instead, my goal was to collect fragments that had much clearer diagnostic details, and particularly the morphological trait that would assist in describing this as a new species: the forked pygidial spine. Compared to previous visits, the giant dalmanitid, Coronura aspectans, was particularly abundant -- in fragments only, of course. In most cases it would be the presence of a single thoracic segment. The piece with the most promise would be the one on the bottom where a good portion is buried in the matrix and awaiting my prep tools. The photos do no justice to these partials. This again is a Coronura pygidium, much of it buried in both the positive and impression side. Some prep will be needed.
In all, a fair outing. The deposition conditions were turbulent, which rarely ever bodes well for finding complete trilobites, but it is a possibility. I am fairly confident that it is just a matter of time and repeat visits that I may come upon a complete one. A complete Coronura would be an incredible coup, but a full Odontocephalus would be invaluable to science. Comments are closed.
|
Kane Faucher
Archives
February 2024
|