346 The American Geologist. Decombor, i898 
crystallization of the pyroxene and adjoining feldspar have 
caused some rather remarkable changes. The products of 
regeneration are confined to the dark areas, and consist of 
lath-shaped anorthoclase, purplish brown augite needles and 
beautifully developed magnetite octahedra, besides the cor- 
roded remnants of the diopside. 
These newly formed minerals resemble very closely those 
of the camptonyte proper and frequently, on the contact, 
grade into them imperceptibly. 
This rather unusual assimilation of a foreign inclusion by 
an intrusive magma, might perhaps speak for a chemical 
affinity between the two rocks. 
Regarding the age of these intrusions little can be said 
with any degree of certainty. It would seem from general 
appearances in the field that the acid dikes are of greater age 
than the basic intrusions — as is the case at Kennebunkport. 
On the Fox islands, however, somewhat further north. Dr. 
Smith (op. cit. p. 64) has found this order to be reversed. 
Here the granitic dikes penetrate both diabase and dioryte. 
and are clearly younger than the latter rocks. At some lo- 
calities they are furthermore distinctly seen to be of more re- 
cent age than the quarjzitic schists, and the overlying Niaga- 
ra and pre-Niagara series. 
The remarkable conformity in strike of the dikes in Casco 
bay with that of the enclosing schists renders it probable that 
they represent the products of volcanic energy, coincident 
with one of the great paleozoic movements of the Atlantic 
border region. It is conjectured that this movement occurred 
towards the close of the Devonian period, contemporaneously 
with the granitic intrusions of Nova Scotia, New Brunswick* 
and Vinal Haven,t but a careful geologic study of the entire 
Maine coast is necessary before this problem can be definitely 
solved. 
*See J. W. Dawson: Quart. Journ. Geolog. Soc, Vol. 44, p. 814. 
tG. O. Smith: op. cit., p. 75. 
