The Maquoketa Shales. — James. 
343 
A recent visit to the typical locality of the shales in Iowa, 
for the purpose of 
collecting the or- 
ganic remains, un- 
der the auspices of 
the United States 
Geological Survey, 
enables nie to give 
details of the rocks 
as they are at pres- 
ent, and*to furnish 
some more definite 
information as to 
their locality than 
has previously been 
published. 
The Chicago, St. 
Paul and Kansas 
City railroad, six- 
teen miles west of 
Dubuque,Iowa, pas- 
ses a little station 
known as Graf. A 
mile beyond, and a 
few hundred yards 
from the railroad 
crossing, is Lattners 
Total 3f jt 3lri. ^^^st Office, a small 
place of half a doz- 
Section of Maquoketa shales on railroad near Graf , Iowa. Virvii«p<? n «!tr»rA 
and a mill or two. Between Graf and Lattners is a cut on 
the railroad and a second one on the wagon road. At the 
former of these places is an ex})Osure of about thirty feet, the 
details of which are as follows : 
Section of Maquoketa-Shales on railroad near Graf, Iowa. 
18. Alternating shales and limestones 8 ft. 
17. Limestones formed of finely comminuted shells, a few. . . . 
perfect 1 ft. 
16. Thin laminated shales, with Polyzoa 1 ft. 9 in. 
15 Limestone with Orthoceras, very abundant 1 ft. 
14. Shale similar to No. 16 8 in. 
13 Shale with Orthoceras 4 in. 
12. Shale 4 in. 
11. Limestone like No. 15 5 in . 
