Deb and me spent the day at our usual Arkona spot, focusing exclusively on the calcareous layers of the Widder Formation in search of more complete Greenops widderensis. We certainly moved a lot of shale with results that may have fallen short of pristine specimens, but far better luck than we'd been having this year. Having zeroed in on a very productive layer, we were finding more relatively complete specimens rather than just bits.
A mixed bunch of semi-partials on the left, and more complete specimens on the right. Sadly, even the complete ones are fairly damaged or distorted - that's just the way the Widder breaks.
What some of these look like after a bit of prep. The one on the left is likely a complete roller, but far too delicate for the tools I have on hand to prep out better. The one in the centre is complete save for the disappointing damage to the upper right cephalon. The one on the right is likely complete, but crushed and would require far more precise tools under a scope to prep.
A heavily pyritized Michelinoceras was among the circumstantial finds. The layers with the higher percentage of full trilobites rests above the hard brachiopod layer, but will also have its fair share of nautiloids and ammonoids. There is also a thin yet productive layer beneath the brachiopod layer that has several ammonoids, but fewer trilobites overall.
Generally, at this level of the Widder Fm, if it is long, thin, and not straight, it will be a pyritized worm burrow. In this instance, we have the appearance of fairly uncommon crinoid stalk which looks to possibly be terminating in a calyx (only some prep will determine one way or another). This would be the first evidence of crinoid I've seen this high up in the formation.
Ammonoids (Tornoceras uniangulare). The two little ones need a bit of a cleanup, while the middle is a whopper at 35 mm. The big one was wedged between two bedding planes in a large slab I was splitting. Although on the hunt for Greenops, this was a trip maker for me. It is fully inflated and intact - not terribly common for the larger ones in that shale as they tend to come out flattened and crushed. The smallest ones at the site (Tornoceras arkonense) come out of the Arkona Formation, and readers of this blog have seen pictures of several ones I've pulled out from there.
The detail on it is also quite good, and might look even better with proper preparation. Those suture lines are fantastic.
But perhaps the real trip-making prize goes to Deb for this find. This is a substantial piece of the arthrodire placoderm, Protitanichthys sp. (I think). It lacks the plate segments of a Bothriolepis canadensis. Most people just find tiny pieces of fish plate, so this one is a really great find. The exact species is not entirely certain to me yet, but the Devonian fish of the Widder are not well described.
So, although we didn't quite find any pristine trilobites this time, the stuff we found by chance in the same layers was more than worth the effort.
Before signing off, for those who would like to see just the trilobites in the expanding collection, I've created a separate gallery page here. It can also be accessed using the green button at the top right of this blog.