THE 
AMERICAN GEOLOGIST 
Vol. V. MARCH, 1890. No. 3. 
ON THE DIKES NEAR KENNEBUNKPORT, MAINE. 
By J. F. Kemp, Ithaca, N. Y. 
The southern coast of Maine is very generally seamed with 
dikes. Localities extending quite from the western to the 
eastern boundaries of the state are cited in Prof. Hitchcock's 
reports for 1861 and 1862. Only at Thomaston, however, 
which is about the middle of the state's sea coast, and at 
Bald Cliff, Avhich is in the extreme southwest, do the dikes 
receive more than passing mention, and in these places 
scarcely more than a paragraph. Dikes belonging to the 
same general series are known in New Hampshire in the neigh- 
borhood of Portsmouth, and are briefly referred to in the New 
Hampshire reports. But here, also, beyond the simple men- 
tion of their existence, little is said. This is not surprising, 
for without the use of the microscope little can be said of these 
dense black rocks, and at the date of the reports the use of 
the microscope in geological work was not general. 
In Massachusetts the eruptive rocks of the coast have 
received more attention, and, as dikes- similar to those referred 
to above are known sometimes of great size, we have much 
more detailed descriptions of them. Prof. W. 0. Crosby 
mentions them in his Geology of Eastern Massachusetts ,• 
Prof. Wadsworth has published some microscopical studies of 
them in the Proc. of the Boston Society of Natural History, 
