Paleozoic Tropics

Some recent water level data. The city is currently dumping rocks on northside beaches to subdue erosion until they figure out what else to do. Waves are crashing on rooftops in Rogers Park. 12/1/2019

After examining the Ceratocephalus goniata  cephalon I found a couple weeks ago more closely, I realized there was more hiding in the matrix. I was pleasantly surprised to find additional thoracic segments still attached to this rare specimen. After a couple hours of careful scribing, it appeared only three segments were preserved, however it had me scratching my head as I had previously thought the front of the cephalon was the back! According to two of my old reference books,   Shrimer & Shrock 1943 and  Armstrong & Armstrong 1962 , both books have the cephalon inverted, causing me to think likewise.  Here is the end result. For a more clear reference, the only other comparison I could find on the Internet was a specimen from Morocco. Here, you can clearly see where the eyes are located and the cephalon in the correct orientation. A strange and incredible creature I am very happy to add to my collection.

On August 17th, I went on a group trip to the Starved Rock Clay Pit. I was specifically looking for some Listracanthus parts, and upon splitting open a large septarion nodule measuring roughly 2ft across, came upon what looked at first like a poorly preserved denticle. Upon returning home and examining more closely, it appeared to have segmentation. After showing photos of the specimen to Dave Carlson and Jack Wittry of ESCONI, it was identified as a rare  Tyrannophontes theridion Shram, 1969. From Wittry's book, The Mazon Ceek Fossil Fauna, "First discovered at Pit 11,  Tyrannophontes theridion was figured and described in 1969 by Shram. Subsequently, similar species were found preserved in the Pennsylvanian black shales of Iowa and Nebraska." Interestingly, nothing is mentioned of the black shales in Illinois. On a side note regarding the mysterious spiny, eel-shaped  Listracanthus that has eluded paleontologists for 150 years ,  a complete specimen has finally b

I discovered an excellent new locality a couple days ago. This locality is isolated, yet close to home, abounding with fossiliferous rocks of the Sugar Run formation( previously known as the Waukesha). In this modern world with everything being paved over and gated off, this can be a difficult task. This is a new species to me. It was found already exposed covered in mud. I didn't think much of at first and threw in my backpack. it is  Ceratocephala goniata, Warder 1838. The cephalon has three pairs of spines on it, which in this case, they are all broken off, however it appears under closer examination, there are a few broken spines hidden in the dolomite unable to be retrieved. Also, this trilobite appears to be blind, as it has no eyes. Encrinurus sp. Supposedly, these cephalons are rare in the Chicagoland area. Disappointed that the left eye stalk popped off during preparation, next time I am using tape! Still, a very nice specimen. I belie

I thought it would be fun to periodically post water level data, since the sea levels are rising. I'll mostly focus on Lake Michigan, Great Lakes, Atlantic ocean. Here are some pictures of disappearing Juneway Beach in Chicago and a link to an article here . 2019

The Paleozoic epicontinental seas consisted of the highest silica concentrations in comparison to the later geologic epochs of the Phanerozoic Eon. Studies show a transition from Cambrian carbonates to predominantly aragonitic marine skeletons beginning in the early Triassic Period as the ocean chemistry and earth's climate changed after the Permian Extinction. In a mutually beneficent relationship, marine organisms use the silica in oceanic waters to build their skeletal shells. Siliceous ooze forms as organisms die and sink to the seafloor. When opal silica accumulates faster than it dissolves, the skeletal fragments are recrystallized and cemented forming chert.  Pictured here is a beautiful fossil coral I found along the Niagara Escarpment near Sturgeon Bay, Wisconsin. The Silurian rocks have resisted glacial meltwaters and erosion as evidenced by the extensive outcroppings, picturesque rocky beaches, and archeological ship wrecks along the peninsula. A first glance an