158 
GEOLOGY OF THE FIRST DISTRICT. 
flow through the channels communicating with the ocean, and through which the waters have 
been drained to their present levels, depositing beds of sand, gravel, pebbles and boulders in 
the eddies. 
5. The fault at Newburgh shows derangement of the clay and sand beds subsequent to their 
deposition, sxidi preceding the deposit of the pebble and gravel beds at that place ; and pro¬ 
bably this, and the dislocations of the slate, which were subsequent to the drift deposits, were 
effected at the period of the quaternary elevation. 
III. DRIFT DIVISION. 
This is intended to embrace the lower part of those deposits that have been called diluvion, 
diluvium, terrains de transport, erratic block group, boulder system, terrains d'alluvion, ter¬ 
rains d’atterrissement, terrains diluviens, altere alluvial-bildungen, etc. 
The deposits and phenomena that I propose now to describe, might have been included in 
what have been described as quaternary deposits ; but as the period of deposition of the mass 
of the drift deposits, as they are described in this volume, was distinct from that of the qua¬ 
ternary, and marked by strong features of distinction, it claims a separate discussion. 
In describing the quaternary, a deposit of pebbles, gravel and boulders was mentioned as 
covering the beds of clay and sand in many places, which was called the upper drift. In 
consequence of these separate depositions of drift, and upper drift, being mistaken for each 
other,* but which are really distinct, (having been produced at different epochs, and under 
different circumstances,) the trains of causes and effects have been ascribed to one epoch. It 
is believed there is abundant evidence of two epochs, of strong currents, with a period of 
considerable duration of comparative repose between them, and that the waters at those epochs 
stood at different relative levels. 
The causes that have produced the drift deposits have acted over alhthe northern and north¬ 
western States and Territories, except limited areas, which will be mentioned in the proper 
place ; and as so many facts have been now observed, as to offer some prospect of generaliz¬ 
ing them, and perhaps arriving at correct conclusions in regard to the phenomena of the drift 
period, I may be permitted to draw facts that tend to elucidate the subject from the various 
sources of information to which I have access. It is a subject to which I have given much 
attention for many years, ^4nd my facilities for observation have been greater than fails to the 
lot of most persons, and le facts have been observed and studied over most of the territory 
belonging to the United k ites east of 97° of west longitude. 
* This mistake may easily be ma ! in many places, even by the most experienced observers; for they are often blended by sub¬ 
sequent causes, and where the clay ind sand beds are absent, cannot always be distinguished. 
