Yesterday was a perfect day to be out. Not only was it national fossil day (at least in the US, but I suppose we can extend that more internationally), but it was in mid-teens, and a good mix of sun and cloud. I made my way to the local Amherstburg/Lucas Fm spot with no real expectation of finding much of anything at all given that I've made so many visits as to deplete its more gainful rocks. I can't say that this trip provided me with glorious finds, but it was a fair outing. I neglected to take a picture of the armour stone I was dealing with. Let us just say that it was big, heavy, and very dense. How dense? I had scored the sides at multiple locations for getting in the chisel, which I was able to sink by a good two inches at each spot without so much as causing a crack -- just tons of rock powder. But, with a couple hundred more blows moving from hole to hole, a hairline crack emerged, and another hundred blows split the beast in two. It is simply the stubborn nature of many Devonian rock formations in Ontario to be brutally hard, with a tendency to shatter rather than split, which makes collecting specimens an added challenge.
Occasionally, these long bryozoans appear, and nearly all of the representatives of this species are mineral stained a deep ochre. I found a few poorly preserved pygidium fragments of Acanthopyge contusa. Due to the silicification, the negative (on the right) are far clearer than the positive to show diagnostic details. More of the same. Pseudodechenlla sp. parts are widespread throughout the "layers," including isolated cheeks and pygidia. I suspect this may be one of the poorer examples, or possibly a Trypaulites. On the right is a partially buried Crassiproetus in a typically busy hash. Thoracic segments are not entirely common in this material, as it seems to favour fragments of cephalons and generally complete pygidia. The size and width of these segments suggests Crassiproetus crassimarginatus. The pair on the right -- "fat man and little boy" -- are also the same species. The two rarest to be found include a pygidium of Mystrocephala stummi, and a partially buried and poorly preserved Echinolichas sp. At this point, I probably have about six examples of this incredibly rare lichid not reported in Ontario rocks.
It would be a fool's errand to assume complete trilobites will ever be found in this material given the depositional conditions, and so one must be content with fragments. It is an interesting lithology which also gives off a kind of petroliferous odour. Unless I start flipping more rocks in the pile at random in the hopes of locating more rocks of this specific horizon, I may have tapped this location out. It has been since late August of 2019 that I have made repeated visits here, and I have performed due diligence in collecting almost every lichid fragment and most intact rare species fragments (Mystrocephala, Trypaulites), if not a few almost complete Pseudodechenella and plump Crassiproetus pygidia. Many of these will likely form part of a museum donation at some point. This was a nice way to spend national fossil day. Although the finds were not showstoppers, I can be content that I bumped into examples of just about every species that can be found in this material, and they all emerged from one single armour stone that took a number of hours to break down. Comments are closed.
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Kane Faucher
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February 2024
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