Figure A-4. Photomicrographs of thin-sections of core samples from Trenton and Black River formations in Carter Lauber No. 12, 6-16N-17W. 

A. 4975 ft--Dolowackestone with anhydrite and baroque dolomite filling fractures in the lower Trenton. Anhydrite patch in lower left is dark, and anhydrite blades in upper right are both clear and dark. Partially crossed nicols.

B. 5085 ft--Silicified brachiopods (Trenton). CN.

C,D. 5085 ft--Anhydrite (A) filling fracture in a dolowackestone (Trenton). C, PPL; D, CN.

E. 5154 ft--Burrowed dolomitic wackestone from the Black River. Dolomite in burrow is finer grained than surrounding rock. PPL.

F. 5200 ft--Completely dolomitized rock; original texture probably was wackestone (Black River). PPL.