Figure A-6. Photographs of core samples from Utica, Trenton, Black River, and Glenwood formations in Sun Bradley No. 4, 11-12N-13W. 

1. 5975 ft--Basal shale (Utica).

2. 6001 ft--Burrow-mottled dolowackestone near top of the Trenton Formation. The primary skeletal components are crinoid and brachiopod debris.

3. 6013 ft--Slightly dolomitic crinoid-rich wackestone (Trenton).

4. 6033 ft  Wackestone with incipient stylolites resulting in nodular to wavy bedding (Trenton).

5. 6055 ft--Nodular wackestone (Trenton).

6. 6076 ft--Nodular, lime wackestone from a shaly interval (Trenton).

7. 6114 ft--Closed horizontal fractures in a slightly dolomitic wackestone (Trenton).

8. 6176 ft--Large chert nodule in shaly wackestone (Trenton). Small vertical fractures are filled with dolomite or calcite.

9. 6204 ft--Skeletal packstone; sample is entirely dolomite with bedding-parallel stylolites (Trenton).

10. 6242 ft--Chert nodule in a lime wackestone (Black River).

11. 6276 ft--Stylolitized dolomitic mudstones (Black River).

12. 6338 ft--Laminated mudstone with increasing amounts of fine dolomite toward base of sample (Black River).

13. 6351 ft--Wackestone with large bryozoan and brachiopod debris (Black River).

14. 6371 ft--Bryozoan wackestone (Black River).

15. 6384 ft--Nodular bedded wackestone with fine stylolite seams (Black River).

16. 6393 ft--Stylolite separating shale-rich layer (top) from faintly laminated finer grained packstone (bottom) (Glenwood).

17. 6405 ft--Dolomitic cross-bedded quartz sandstone from the Glenwood-Prairie du Chien contact.