|
EVIDENCES OF GLACIATION 221
|
||
|
|
||
|
at
about its highest point, and exhibits a clean face of rock. Some
initial work in the matter of opening this pass may have been
accomplished by the glacier itself.
Teachers
will find a wide and complete literature of the Ice Age. No subject
seems to have been more thoroughly and repeatedly examined. In special
treatises, in essays, lectures, and large compendiums, every aspect of
this fascinating topic has received ample, almost tiresome,
elucidation. Amongst the great number of possible books which might be
mentioned, there are three essays of eminent value which can be
consulted with profit and are readily found. These are T. C.
Chamberlin's " Terminal Moraine of the Second Ice Sheet," in the Third
Annual Report of the United States Geological Survey, Professor I. C.
Russell's " Glaciers in the United States," and Professor Wright's "
Ice Age in America." The information, suggestions, and illustrations in
these works can be made most helpful in the teacher's efforts to
explain to her pupils the " Evidences of Glaciation in and about New
York."
PEAT IN POST-GLACIAL FORMATIONS
Among
alterations of the surfaces, drainage changes, and superficial
deposits, either marginal to the larger areas or accumulative in
broader interior spaces, the growth and decay of vegetation at various
points, in swamps, sink-holes, ponds, and marshes, has left within the
city limits extensive peat beds. The very important morainal kettle (?)
hole, drained and cleaned in the Moravian Cemetery on Staten Island
(Richmond Borough), in which a mastodon's tooth was found, was
littered with vegetable débris. Such material under favorable
conditions becomes macerated, compressed, saturated with humus acids,
and progressively altered, until a mass of porous, peat-like texture is
formed, which is practically indestructible.
A
very extended bed of this nature was uncovered in Centre Street during
the preparatory work for building the loop Subway, connecting the East
River and Williamsburg
|
||
|
|
||