Sunday, August 21, 2011
The fossil pictured is a very interesting find. It appears to me that this Archimedes sp. bryozoan has a holdfast or root like structure at its base. Another nice feature of this bryozoan preserved in matrix is the Fenestella like netting still somewhat attached to the screw like structure of the colony.
Next two pictures show magnified views of this root like structure. The microscope images are over exposed somewhat due to the halogen light source. It is difficult to see but the line pattern on the main Archimedes screw surface matches that found on the thinner wire like root structures.
Last two images give sense of size/dimensions of the bryozoan fossil.
Fossil found in Crawford County, Indiana in Mississippian Period age matrix.