Thaleops ovata Price: SOLD

Thaleops ovata (free standing) Trilobite:  width – 38.76 mm (1.52”)            Length – 20.75 mm (0.81”) Matrix: length – 63 mm (2.48”)       Width – 49.4 mm (1.94”) Mifflin Member, Platteville Formation Grant County, Wisconsin
Here is an opportunity to own a type specimen of the Genus Thaleops from the type formation. This Thaleops ovata has been prepared as a free standing example that clearly showcases the wonderfully elongated genal spines unique to the genus. As with most rare or hard to find trilobites there are a couple of condition issues to mention (no restorations have been performed): the left eye, as viewed dorsally, was missing when found and a small chip off the tip of the right eye is also missing. The specimen displays beautifully, contrasting nicely between the caramel colored exoskeleton and the cream colored matrix. No restorations have been made to this individual.

Thaleops ovata The UMV was recognized as a significant economic resource for the young United States early in its history. The area was known for its lead deposits by the late 1600s and by 1700 British and French maps of the area labeled the lead mines. Following the Louisiana Purchase in 1803 the region technically remained the possession of the local Indian tribes. The lead producing region was purchased from the Indians in 1828 for $20,000.00 but the fox & sac tribes resisted resulting in the Black Hawk war that ended with defeat and subsequent sale of 6 million acres for $640,000.00 in 1832. This is the background to the first geological evaluation of the region. In 1837 David Dale Owen, an Indiana geologist wrote a proposal to the U.S. congress to conduct a reconnaissance of 11,000 square miles in what is now northeast Iowa, northwest Illinois and southwest Wisconsin. Aided by 139 assistants this survey was conducted in 1839. It is interesting to note that lead production from the region peaked by 1848. One of the assistants to Dr Owen was Timothy Abbott Conrad, an early paleontologist and geologist who described the first known trilobite of the region collected during this survey – Thaleops ovata. T. ovata has been mentioned in various papers as being found in formations ranging from the Blackriverian to the Richmondian. In reality the species ovata is restricted to the pre-Chatfieldian (Blackriverian) Platteville Formation in the upper Midwest, the Plattin Formation of Missouri and possibly equivalent formations in the northeastern U.S. and Canada. Even the most recent revisional paper on the genus Thaleops (Amati & Westrop, 2004) got it wrong when they perpetuated the myth of occurrences even to the point of the wrong type formation.  Recovered from what is now known as the Mifflin Member of the Platteville Formation, Thaleops ovata only accounts for approximately 10% (DeMott, 1987) of the Mifflin trilobite fauna. The species is a unique and beautiful trilobite characterized by long sweeping genal spines, elongated eyes, a pitted ornamentation and a well defined pygidial axis.