i8o The American Geologist. September, i9oi. 
area covered by this section, these may be considered rehable. 
This is especially the case, since all the strata entering into the 
section are ofif-shore deposits, with a minimum of coarse 
detritus, and hence of a character which remains uniform over 
a large area. 
The following succession of strata in this region has been 
derived from the records of the Churchill well, the location of 
which is near the southern end of the section in Alpena. 
The mouth of the well is near the level of lake Huron, 
and above the coral limestone of Alpena. This rock is the mid- 
dle member of the Traverse (Hamilton) group of Michigan, 
and hence the entire upper portion of this group is unrepresent- 
ed in the well record. At a depth of over 1250 feet, the well 
ends in the salt beds of the Salina group, having penetrated the 
entire lower Devonic rocks of the region. 
SUCCESSION OF STRATA IN THE CHURCHILL WELL AT ALPENA, MICH. 
FEET 
1. Sand and boulders 41 .0 
2. Hard white (light colored) limestone 25.0 
3. Shale 9-0 
4. Very hard white limestone T 49.5 
5. Shale 2.5 
6. Extra hard gray limestone 40.0 
7. Blue shale 20 . o 
8. Hard white limestone 34.0 
9. Shale, 7 feet white and slimy, possibly gypsum (?) 18.0 
10. Hard white limestone 23 . o 
11. Very' sticky blue shale 27.0 
12. Hard white limestone 32.0 
13. Shale 3-0 
14. Hard white limestone, upper 7^ extra hard 39.0 
15. Shale 24.0 
16. Hard white limestone 5.0 
17. Shale, mostly blue 52.0 
18. Hard white and gray limestone, mostly extra hard 63.0 
19. Extremely hard (flintv) limestone 39.0 
20. Shale 25 . o 
21. Hard gray and white limestone 103.0 
22. Shale 20. 
23. Hard white limestone 86.0 
24. Sandy lime shale 10. 
25 . Hard white limestone 468 . 
This carried the drill down into the rock salt of the Salina group. 
