IOWA ACADEMY OF SCIENCES. 
73 
Number. 
SECTION. 
Thickness in 
feet. 
Depth in feet 
22 
21 
Dolomite, llg’ht gray 
15 
1600 
Limestone, lig’ht gray, with some chert and sand 
30 
1630 
Drilling’s washed away 
40 
1670 
20 
19 
Sand, clean, white 
30 
1690 
Dolomite, yellowish, sandy 
35 
1735 
375 
2000 
18 
Limestone, dark g’ray'i do'omitic 
5 
3005 
17 
Limestone, dark g’ray, nearly pure 
5 
2010 
16 
Limestone, dark gray, arenaceous 
30 
2030 
15 
Dolomite, dark g'ray, arenaceous 
30 
3050 
14 
Dolomite, rusty gray, with sand and shale 
45 
2095 
13 
Dolomite, rusty gray, mixed with pure limestone 
30 
2115 
13 
Dolomite, rusty gray, with much pure limestone . 
15 
2130 
11 
Limestone, dark gray, with some little sand 
15 
2145 
10 
Limestone, mixed with sand and shale 
80 
2235 
9 
Limestone, brownish gray, with much sand 
10 
2335 
8 
Sand, light gray, with some lime 
15 
2250 
7 
Sand, light gray, dolomitic 
30 
2270 
6 
Sand, white, fine grained 
5 
2375 
5 
Sand, rustv, coarser grained 
85 
2360 
Drillings washed away 
40 
3400 
4 
Sandstone, very hard (13 hours in oriHing 5 feet), many pink'sh grains 
resembling quartzite; mixed with much shale and dolomite from 
above 
5 
2405 
3 
Same as No. 4, but with some little slate 
5 
2410 
2 
Slate, very dark, compact 
10 
2420 
1 
Slate, same as No. 3, but harder 
10 
2130 
Drill stopped in pure slate, at 3,430 feet. 
SUMMARY. 
1 
Number. 
FORMATION. 
Thickness. 
Depth. 1 
66 
Pleistocene 
18 
18 
64-65 
Augusta— Upper Burlington 
60 
78 
62-63 
Augusta — Lower Burlington 
33 
110 
59-61 
Kinderhook 
330 
440 
55-58 
Devonian. 
248 
688 
50-54 
Silurian 
180 
868 
48-49 
Maquoketa 
42 
910 
45-47 
Trenton 
45 
955 
1 
