This will be a relatively short post as I begin gearing up for another multi-day adventure out of province. As I wait on a few more regional spots, I made a casual return visit to a local spot that is a Devonian salad of southwestern Ontario formations. The only notable trilobite find was a pygidium of Trypaulites calypso. Ludvigsen (1979) tells us that this species is not reported in Ontario rocks, but does appear in correlative strata in both Michigan and New York, which is to say it occupied both basins. I performed some preliminary scribing just enough to ensure that the diagnostic details would square with the certainty of proper identification. I have found quite a number of this species in Amherstburg and Dundee Formations, but the nature of the preservation has generally meant that they were either silicified or appearing as a steinkern. In this instance, the ornamentation is clearly visible. One of the key diagnostic traits of this species would be the backward-facing axial nodes that lends it a kind of sagittal ridge appearance, in addition to the number of pygidial pleurae, which has a variability of between 10-14 (see Lesperance, 1975). A focused image-stacked photo reveals the very fine granules on the shell. It is fortunate that this was preserved in such good condition, as many of the recorded examples do lack the detailed prosopon. This is not by far a tremendously exciting find, but certainly of interest for its detail. But this is just the beginning of the end of the season, and autumn is the ideal time to kick it up a notch due to the cooler temperatures. I've already been fortunate this year in having made two extended trips far from home, and I can safely say that this has been the very best collecting year so far despite the ever narrowing prospects for fossil collecting in Ontario. It has taken a lot of diligence and sweat, but I think I may have graduated to "serious and dedicated collector" as opposed to "weekend warrior." The efforts, although not all gainful, have certainly paid off. Stay tuned for what the remainder of this season may bring! UPDATE: Just a quick and neat find today barely a few minutes' drive from my house, amongst river transport rocks, all Dundee Fm. I made a run to the hardware store to replace a missing brick hammer, and it was the last one in stock. I checked out a new, very small, spot that would only take a few hours to exhaust. Breaking in the new hammer, after no more than ten minutes, a full prone Eldredgeops rana that will measure about 50 mm when prepared was staring up at me from a fresh split. Sadly, some of the shell is missing or stuck to the impression (which I kept), but I can do some light restoration with Milliput. A pretty robust one! I seem to be able to find trilobites anywhere. UPDATE 2:
And this just landed in the post on the eve of my journey to la belle province. It was listed as Mucronaspis zagoraensis, but on account of the blunted genal spines I was leaning toward this actually being Dalmanitina socialis, which is also found in the Ktaoua Fm in Morocco. This was later confirmed by my friend and trilobite expert, SM (my thanks!). It's an internal mould, and about 7 cm long with the caudal spine in place, with just a bit of crush damage on the left side of the cephalon, missing an eye. Comments are closed.
|
Kane Faucher
Archives
February 2024
|