C. M. Wetherill on the Artesian Well of Lafayette, Ia. 243 
_ Geology of the well.—The order and character of the rocks in 
Proceeding from a point west to one east of Lafayette, is from 
information furnished by D. Brown, State Geologist, as follows: 
1. Seams of Coal. 
2. Mountain Limestone about 200 feet in thickness. 
8. Clay Sandstone (Devonian) about 600 feet. 
4. Delphi Slate varying from 25 to 100 feet, and thinning to 
the northwest, 
5. Grey Limestone (Upper Silurian). . 
- Blue Limestone (Lower Silurian). 
€ dip of these rocks is about 25° to the south of west, and 
atan angle of 50 feet fall to the mile. This westward dip is 
htained until the Mississippi is crossed, when the dip is east- 
sot 
~oved the Clay Sandstone, not a trace of which was discovered 
n boring the well. The Delphi Slate was the first rock reach 
