I spent a sustained eight hour day at my new spot, by far the longest uninterrupted dig time there. After a total of about 14 hours, I can proudly say that I have found evidence of five genera of trilobites. And, hey, it's my birthday today. Woot. I was once again able to find my "all-day rock," which is a term I coined to mean the kind of rock that takes most of the day to split, and from which the bulk of the finds are made. Finding that rock is a challenge, and makes the difference between a productive trip and one where it is a complete skunk. In this case, the "giving rock" lasted me about three hours. I'll kick the photos off with something pretty. This material occasionally contains vugs that are calcite-lined, suggestive in part of some diagenetic remineralization. Most of the fossils regularly come out bone white on account of silicification, but not always. In any event, the calcite crystal formations here are quite neat as they form rhombohedrons. If they came out easily from the matrix, these non-trilobite finds made it into the collecting bucket. I am pretty sick of rostroconch. This slab is a typical example of how they can infest a bedding plane. Zoom in and count them. Stromatoporoid cap showing distinctive mamelons. And, yes, those gloves are wrecked. I go through a pair of these once a trip. Already, my brand new boots have a tear, both my new fossil pants have their butts blown out, my backpack is falling apart, and my new chisel from last autumn is becoming a mushroomed nub. The first and only example of Crassiproetus I've located in this material. On the right is a Pseudodechenella. I don't really keep these as they are numerous, but this appeared in a slightly different layer that contained rugose coral that were purple and pink. Some bizarre mineralization going on. More Odontocephalus frontal margin denticles. It is pretty frustrating not to find much more than that for all the volume of rock I go through! "By their impressions, ye shall know them." The negative of an Anchiopsis anchiops. The positive on the right is in such poor shape that it was not worth fussing over. Never fear -- I got my fill of them! I do have my doubts about the one on the bottom left: I extracted that one from a different layer that was in a car-sized block and so hard that each hammer blow caused my whole body to vibrate while only small shards and powder was produced. I luckily got this out without shattering through it, and it continues a good distance into the rock (judging by what I can see on the other side). Some scribe work will tell more of the tale of this tail. Some quick scribing of a few of the ones on the right will also reveal them in full. What I suspect to be a Coronura sp. The giveaway is the very narrow axis and wide pygidium with plenty of ribs. This one full would have been pushing almost a foot long. Sadly, the positive had long since eroded away. I found the impression set vertically in a joint in a large block. The rest of the rock had a few isolated segments. It was also the "all day" rock I spoke of above. Lastly, these two fragments. They look to be related, as negative and positive of each other, but actually occurred in different parts of the (again, "all day") rock. The pustular surface, appearance of furrows, and shape causes me to speculate that it could be another Coronura fragment, but I've asked for a second opinion. It is reminiscent of the Phalangocephalus cephalon examples I was gifted a few years ago that come from Montague, New Jersey. I'll update this when I hear back.
UPDATE: And so these all are Coronura aspectans. Confirmed! These three pieces plus the one I found on the first day brings me to a total of four examples of this species. So, not bad for three visits. I managed to add one new trilobite genus to the collection, while also acquiring more examples of two others. It may be time to let this site cool down for a bit while I get back to my list of prospect sites (should my field companion be reading this, as she does from time to time!). _____ The current tally of Ontario bugs has grown a wee bit in the last eight months by four (in bold). These are just trilobites from Ontario that I've collected. A pretty good showing of Devonian bugs, with a few that I know some serious collectors don't have examples of. In terms of Silurian, absolutely zip. The Ordovician list is pretty sad, too, but access to Ordovician spots is problematic on account of distance and opportunities these days. I've removed the Terataspis grandis from the list as I cannot be certain the fragments I have do not actually belong to one of the other echinolichines I more commonly find at my Amherstburg Fm spot. Devonian (17) Acanthopyge contusa Anchiopsis anchiops Coronura aspectans Crassiproetus canadensis Crassiproetus crassimarginatus Greenops widderensis Echinolichas eriopis Echinolichas hispidus Eldredgeops iowensis southworthi Eldredgeops rana Mannopyge halli Mystrocephala stummi Odontocephalus selenurus Pseudodechenella planimarginata Pseudodechenella rowi Trypaulites erinus Trypaulites calypso Silurian (0) NONE Ordovician (12) Achatella achates Amphilichas ottawaensis Calyptaulax callicephalus Ceraurus sp. Flexicalymene croneisi Flexicalymene senaria Isotelus gigas Isotelus “mafritze” (A and B morphs) Leviceraurus mammiloides Pseudogygites latimarginatus Thaleops sp. Triarthrus eatoni Comments are closed.
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Kane Faucher
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February 2024
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