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Introduction Rockford Fossil and Prairie Park is on the site of an old clay quarry and brick factory, the Rockford Brick and Tile Company. The slate mined there was ground up to make clay for bricks and tiles. One of the nice things about the park is that by far most fossils are not just casts, but a fossilization of the shells themselves. I was there for about 5 hours. In all that time, I saw only one other car/group — a woman with her three small children, and several footprints in the mud. The nearby river, now the Winnebago, was once called Lime Creek, and that is where the bedrock in the area got the name the Lime Creek Formation. The formation is Upper Devonian (Frasnian Stage, ~382 - 372 million years ago). If you are ever going to visit the park, there is a nice, readable account of the area’s history and geology that seems to have been written by a teacher for a summer course she was teaching: https://www.exploreiowageology.org/assets/text/GeologyofIowa4Teachers/2015/Projects/LauraWalter.pdf. Rockford itself is small town, with a 2019 population of 819. To get to the park, you drive through town down a couple of streets with a few one- to two-story small businesses and then a couple of residential streets, and that seems to be the town. Lots of farmland on all sides. The Site The fossil-collecting area of the park is huge! It consists of an extremely long connected series of deep, wide pits; perhaps more of one long, winding single pit. The pits are about 20 meters deep. Some of the upper faces of the pits are vertical, but almost everywhere there are slopes of eroded rock and washed-down and fossil-filled, gray, clay-rich soil. Here are a series of pictures that I took from one side of the pit(s). I tried to keep the left side of each photo visible on the right side of the next, so that you can get an impression of how large this area really is. The photos start with me standing in the parking area. It had rained moderately the day before. I don’t know to what extent the water you see in this and the next photos dries up often. This photo at the other end of the parking lot and a little way down a trail. A little further along the trail and 90-degree turn here. Still further along the trail. (The reddened slope is not geologically distinct. It just has a lot of old pieces of brick dumped on it.) I’m not sure what is on the other side of that far ridge. The pit could go on still further. A portion of the prairie part of the park. And now, on to the fossil hunt! The gravel parking lot ends and you find a level area several meters wide along the upper rim of the pit’s right corner (as you’re facing it from the parking lot). Here, it’s as though you had a huge brachiopod hashplate whose matrix magically weathered away, leaving you with an abundance of loose shells. You could sit in one spot and easily pick up over a hundred small fossils without shifting your position. In this area, it felt more like picking up shells on a beach than hunting fossils. I put a bunch into a zip-lock plastic bag with the thought that they would look nice in a small glass bowl of assorted brachiopods: Then I climbed down the slope a little further. Most of the areas I explored were a mix of loose small rocks, some containing fossils some not, and fossils that were either loose or very easy to loosen from surrounding matrix. These may be some trace fossil burrows. The sorted finds My favorite, for some reason, are these Schizophoria iowensis. Maybe because they’re so plump. Very fulfilling to pluck from the surrounding clay/shale matrix. Found mostly in the middle levels of the pit. Dorsal view and side view: Cyrtospirifer whitneyi (my second-favorite type): Spinatrypa rockfordensis. Quite flat, reminded me of old Roman coins. (When living, these creatures had spines that extended from the margins of their shells. The spines are fragile and none survived on the specimens I saw.) The most common fossil I found there were these. They may be Devonoproductus walcotti. They have a round, convex ventral valve. The dorsal valve starts out convex then turns concave (second picture). A type I haven’t identified that resemble the Devonoproductus, but whose dorsal valve is robustly convex (second picture): Some specimens that I found only single valves of. I think they are Sulcatostrophia camerata. Found mostly in the upper layers. Finally, one extremely flat brachiopod that I haven’t identified. I don’t know whether it was this flat when it was alive or whether it was flattened over time (ventral, dorsal, side views) That’s all for now. I found a smattering of gastropods and horn coral, a few bryozoans and crinoidal columns, some likely trace fossil worm burrow casts, and a possible small plant-type fossil. I’ll post these in this topic later when I have more time.

A little over a week ago I moved to Louisiana. On the way down I tried to set aside a little time to stop at a few places and collect. I made a couple short stops at roadcuts south of Minneapolis to some success (brachiopods, rugosa, Flexicalymene, etc.) but the most impressive stop was the Fossil and Prairie Park outside of Rockford Iowa. It's surely well known by collectors in Iowa but I found it by accident while researching my route down. A town that owns it's paleontology history is always nice and the town was beautiful. I wish I had more time to hang around and try the bar on Main. Outside Rockford is the Fossil and Prairie Park, the site of an old quarry. The Visitor's Center was unfortunately closed while I was there but there's lots of history and information online. Fossils were absolutely everywhere and it was hard to pry myself away after only an hour there. Easy collecting. The trails looked nice but again I did not have time to check them out. I still haven't had time to go through and identify and catalog everything but I have a general idea on what most are. I felt like if I didn't get around to posting this stuff this week I was never going to. Bad pictures, need to set up a light area here. I also didn't think to pack any of my scale references apparently. A very nice place for sure and occasionally people turn up rarer things such as cephalopods. Still, the diversity is impressive even among the brachiopods.