42 
IOWA ACADEMY OF SCIENCES. 
Wells drilled on the higher ground at Hopkinton, reach the 
Maquoketa shales at a depth of 90 feet. The bed of the river 
at the mill at South Hopkinton, must be within a few feet of the 
shales. Owing to the reversal of the dip the Pentamerus beds 
that are exposed at the surface at Hopkinton are found at 
“Devil’s Back Bone,” in northwestern Delaware, and the cleft 
casts of the ventral valve are known to the summer visitors of 
that somewhat noted locality, as the “Devil’s Claws”. The 
same beds extend over into northeastern Buchanan, and any- 
where in that region the shales may be reached at a depth of 
about 100 feet. 
The proximity of the shales to the surface over so wide an 
area is not without its economic significance. The surface of 
the shales is everywhere a water-bearing horizon, and so unfail- 
ing wells may be obtained over many square miles by boring to 
only a moderate depth. The drouth of last summer has turned 
the attention of farmers, especially the cultivators of vegetables 
and small fruits, to the desirability and practicability of irriga- 
tion, and there has been manifested a very general desire for 
information as to the depth at which unfailing supplies of water 
may be reached. The next summer will witness some practi- 
cal experiments in this direction, particularly at Hopkinton, 
and the water supply, it is expected, will be found in the Maquo- 
keta shales. 
OCCURRENCE OP MEGALOMUS CANADENSIS, HALL,, 
IN THE LECLAIRE BEDS AT PORT BYRON, 
ILLINOIS. 
BY WILLIAM HARMON NORTON. 
This common fossil of the Guelph of Canada has not been 
noted in the Le Claire beds of Iowa, or their immediate exten- 
sion into adjacent states. Its occurence, therefore, at Port 
Byron, Illinois, in the Barrett quarries one and one-half miles 
north of the town, is of special interest, since it shows a range 
