94 
TACONIC SYSTEM IN MAINE. 
V. THE TACONIC SYSTEM IN MAINE. 
Remarks on the geology of the country between Portland and Waterville. Origin and position of the granite 
used in construction. Slate of Waterville: similarity of all its subordinate beds to those of JVew-York. 
Breadth of the taconic slate. Reference to the JVereites of Waterville. Similarity of the Kennebeck valley 
to the Hoosic valley in JVew- York. General remarks on the rocks between Waterville and Belfast. Examina¬ 
tion unsatisfactory at Belfast. Rocks of Camden. Megunticook mountain. Fox islands. Limestone of 
Thomaston. 
The valleys of the Kennebeck and Penobscot, together with a wide belt of country upon 
the Piscatacjua, furnish many important facts in support of the Taconic system. I was 
first convinced of the importance of the rocks in these valleys, from a specimen of slate 
which was furnished me by my friend Prof. A. Hopkins, of Williams College, from the 
Kennebeck at Waterville, upon which I observed peculiar markings, so strongly resembling 
those of the JVereites figured by Mr. Murchison in his Silurian System, that I could not 
doubt that they belonged at least to that genus. As this slate appeared identical with the 
Taconic slate of New-York, I deemed it important to visit the region which furnished the 
specimen. I accordingly visited Waterville, going by way of Portland, for the purpose 
of passing over as much of the adjacent territory as possible. Before proceeding to relate 
the facts concerning this slate, I will avail myself of the opportunity to say a few words 
upon the rocks between Portland and Waterville. 
The rocks in and about the city of Portland, and onwards through Brunswick, belong 
to the Primary system. They consist of schists, gneiss and mica slate, mostly of the same 
character as those of Massachusetts. They are traversed like them with coarse granitic 
veins, abounding in tourmaline and other minerals peculiar to such veins. Besides the 
coarse variety of granite, one of a beautiful light grey is associated in beds with the same 
schists. This variety is almost entirely destitute of the fine minerals so abundant in the 
coarser kinds, and which traverse the schists in rather narrow veins. I hardly need re¬ 
mark that it is the grey and uniform rock which has been so much employed in construc¬ 
tion. The most interesting fact which I observed in relation to this rock, was, that it 
occupies usually the summit of the hills, appearing there as the capping stone. On exa¬ 
mining several of these hills which had been opened as quarries, I found that the granite 
was quite limited, and that the entire mass had been removed ; that the bed rested originally 
upon the edges of the nearly vertical mica slate ; and, in fine, all that remained of those 
beds, were the veins through which the granite seemed to have issued while in a molten 
state. These veins are from one or two inches to a foot in thickness. I know that this is 
not a new fact in geology; but I had not seen any statement to this effect in the publica¬ 
tions of the day. Granite of the same kind, but of a coarser grain, forms large beds in 
some parts of Massachusetts, and has probably a similar origin. In New-York, granite 
seems also to have overflowed some of the beds of primary limestone. 
I have introduced a notice of the primary rocks, and of their igneous character, prin- 
