Dikes near Kennehunkport^ Maine. — Kemp. 133 
Kennebunkport the evidence of three epochs from the in- 
tersection of the dikes is less abundant. The porphyritic 
type --Prof. Hitchcock's first class, — is represented, but a case 
of faulting by the latter ones I can not cite. The second 
series are the ones most developed, and even here their 
general northeasterly direction can be remarked on the map. 
The third brown scoriaceous variety is also often seen and 
evidently faults the others. 
At Kennebunkport the dikes are not of great width, aver- 
aging generally five feet and less. Only one or two run as 
high as twenty. But their persistence for their small width is 
remarkable. One may be seen on the map to start from the 
point called Spouting Cave, and run along the east side of 
cape Arundel nearly half a mile, yet nowhere above eight or 
ten feet in width, and frequently less. It then runs under the 
water, and may go farther. Dikes not more than a foot wide 
frequently run several hundred feet, as on the eastern side of 
Damon's point, and small stringers but a few inches run forty 
or fifty feet and pinch out very gradually to a feather edge. It 
seems remarkable that they were able to preserve their liquid- 
ity for any such distance, but it is easily noticeable macro- 
scopically, that where such is the case the dike is very com- 
pact, well nigh glassy in structure. 
Sometimes a tendency is exhibited to separate into rude 
basaltic columns across the dike, but in general they are quite 
solid masses. Rarely spheroidal weathering is seen, chiefly 
in the dikes of the third epoch. They then break up into 
rounded masses, six inches and less in diameter, but always 
in the middle part. In the larger dikes there are frequently 
to be seen Smaller dike-like masses running through them, as 
if the yet molten interior had oozed through cracks in the 
outer hardened crust, as is frequently to be seen in our mod- 
ern lava flows from active volcanoes. 
The rocks will be treated in reference to their microscopic 
structure in the order of their formation. The granites are the 
oldest. The rock occurs both as bosses or knobs and as dikes, 
which are undoubtedly off'-shoots from the larger bosses, even 
when the connection is not visible. On the map, dikes 2, 9, 
16 and 28 are granite. They are about one or two feet wide, 
and often extend two or three hundred feet. They consist of 
quartz, microcline, orthoclase, plagioclase, andbiotite, but the 
