1894. } NEW YORK ACADEMY OF SCIENCES. 11 
of disturbance is coincident with the line of the terminal 
moraine from Nantucket to northern New Jersey; that the 
phenomena of folding and crumpling in the strata of the coastal 
plain are only to be found where the moraine has advanced over 
some portion of the plain; and that these phenomena cease 
abruptly where the moraine bends away from or finally leaves 
the plain. 
It may perhaps appear unfair to assume that Prof. Shaler, 
having restricted his studies to Martha’s Vineyard,* would 
extend the theory which he has so ably advocated for that 
locality, so as to include Long Island and westward. On 
the other hand the opinions of the observers previously quoted 
are equally worthy of consideration, and it is certainly within 
the bounds of fairness that one who has not been restricted to a 
single locality, but has studied the region as a whole, should be 
allowed to say that the phenomena are identical from one ex- 
tremity of the region to the other, and that any theory advanced 
to account for them in one section must also account for them 
in every other.section. One series of cause and effect has been 
instrumental throughout,—either mountain making forces, ice 
action, or some other agency,—and inasmuch as the two men- 
tioned are the only ones which have been advocated we may 
confine ourselves to a discussion of these, and the relative 
claims which they have upon our confidence, considering them 
both on @ priori grounds and by actual weight of evidence. 
DISCUSSION OF FACTS IN CONNECTION WITH THE LINE OF THE 
TERMINAL MORAINE. 
Beginning with Martha’s Vineyard we may consider the facts 
there as types, on a more extended scale, of those elsewhere on 
the line of the moraine. The island consists essentially of a 
series of hills on the north, composed of a core of cretaceous 
and post-cretaceous strata, tilted and folded, flanked on the 
north and capped on the top by bowlder till, which gradually 
merges into water assorted material on the southern flanks and 
extends over the plains beyond. Most of the sections given in 
Prof. Shaler’s papers show this structure-admirably and render 
any further illustration of the locality unnecessary. I have, 
* Mem. Since the above was written, at the Brooklyn meeting of the Geological 
Society of America, Prof. Shaler was enabled to hear the argument and to briefly dis- 
cuss it. He stated that he had visited both Staten Island and northern New Jersey, 
and while admitting the possibility of ice action as the cause of crumpling and other 
disturbances in the plastic strata in these localities, could not admit its application to 
Martha’s Vineyard on account of his conviction that the topography of these hills had 
been determined in pre-glacial times. 
