12 TRANSACTIONS OF THE [oor. 23, 
Head, and it is of interest to note that Prof. Shaler, one of the 
latest observers, likewise argues for a somewhat similar idea, 
viz., mountain-building forces, in order to account for the dislo- 
cations and elevations of the strata. 
Doubtless recognizing the substantial agreement between 
these widely separated sources of information, we find, in the 
International Encyclopedia, which bears the imprint 1892, 
under the caption ‘ Martha’s Vineyard,” the statement that 
“« * * * At the w.end of the island, is Gayhead, an abrupt 
and bold coast-line eminence, which is said to be of volcanic 
origin.” ° 
Under the above circumstances, it therefore becomes of im- 
portance, in case.any other interpretations of the facts are war- 
ranted, that they should be made known, together with any ma- 
terial and observations upon which they may be based. 
My own investigations on Staten Island and Long Island,* 
continued thr ough many years, satisfied me that a single series 
of cause and effect had produced the phenomena of folding, 
elevation, dislocation and transportation of the cretaceous and 
post-cretaceous material which we find there in connection with 
the terminal moraine. 
If we examine the moraine throughout Long Island and in 
that portion of it on Staten Island, which is to the south of 
former cretaceous or post-cretaceous areas, we find that the clays 
and other incoherent strata have not only been eroded but 
plowed up in masses, or the strata frequently folded or squeezed 
up and shoved ahead by the advancing ice sheet, which, upon 
melting, left them as hills or ridges of dislocated, contorted 
material, covered to a greater or less extent by the englacial and 
superglacial till. In some instances the clays are interbedded 
with the till, forming a part of it and just as erratic in their dis- 
tribution as are the accompanying bowlders. In other instances 
the till appears merely as a mantle over the distorted clays 
below. The northern flanks of the hills are usually deeply cov- 
ered with the till, which thins out to a feather edge on top, 
merging into more or less modified and stratified material on the 
southern flanks. A miniature ideal section of this description may 
be seen at Arrochar, Staten Island, in the new cut made for the 
*“The Paleontology of the Cretaceous Formation on Staten Island.’”’ (Trans. 
N. Y. Acad. Sci. XI. 96-104.) 
‘‘ Additions to the Palzobotany of the Cretaceous Formation on Staten Is- 
land.” (Trans. N. Y. Acad. Sci. XII. 1-12.) 
“Plant Distribution as a Factor in the Interpretation of Geological Phe- 
nomena, with Special Reference to Long Island and Vicinity.” (Trans. N. Y. 
Acad. Sei. XII. 189-202.) 
‘*Preliminary Contribution to Our Knowledge of the Cretaceous Formation 
on Long Island and Eastward.” (Trans. N. Y. Acad. Sci. XII. 222-237.) 
