Satka was one of the first microfossils to be described from the Belt Supergroup. It was found in grey and black shales along Highway 89 near the town of Neihart by Robert Horodyski, and first described in 1993. At the time the names of these kinds of fossils were still being worked out, but the images from Dr. Horodyski’s publications are generally good enough to make a match. Satka’s key attribute is that it’s composed of a tessellated pattern of polygonal plates held together by a thin, mucilaginous outer layer. The fossils have since been described from early Mesoproterozoic/late Paleoproterozoic shales in Australia, China and India.
I recently discovered a few isolated specimens of Satka in the Greyson Formation of the Belt Supergroup, the first time this fossil type has been found in this unit. The specimen above is torn a bit, but overall it’s in pretty good shape and shows the key morphological features that let us resolve its form taxonomy. Nobody knows for sure what it is- its complex surface structure may indicate a eukaryote, but then again it could also be some kind of colony of smaller bacteria held together by a simple envelope.