Perry.] 136 [February 28, 
In addition to these older beds there are possibly others lying in 
patches, in the same neighborhoods, which are of marine origin. Still, 
without special and probably long-continued examination of these 
deposits, it would be plainly out of the question to indicate just how 
much of them is due to fresh water agency, and how much, if any, to 
oceanic. So long as there is no positive evidence the presumption is 
that they are not marine. Substantially true is the same in regard to 
the stratified superficial deposits along the coast of Massachusetts, 
New Hampshire and Maine. In fact, on the sea board generally it is 
often exceedingly difficult, in some cases perhaps utterly impossible, 
if no organic remains be found, to draw the line of demarcation be- 
tween these beds. Thus, as should be evident, the respective char- 
acters of these strata cannot be determined when they are simply 
looked at theoretically ; they will by no means yield up all their se- 
crets, if they be merely lumped off in mass. Because one is sure of 
the origin and use of certain layers, for instance in Maine, he having 
studied them critically, as they are seen in place, it does not follow 
of course that he knows the exact age and character of others in 
Massachusetts, Rhode Island, or Connecticut, simply because they 
happen to be Post-Tertiary and stratified. The several deposits in 
different localities can be known. only as there is close and accurate 
observation of each of them, in their respective places of occurrence. 
In the basins of Lake Champlain and of the River St. Lawrence, in 
Southern Maine and in Eastern Massachusetts, both kinds of beds 
occur. In some cases their discrimination is easy; while in others it 
is very perplexing to attempt, if it be not entirely beyond one’s 
power, to determine with certainty to which series a given deposit be- 
longs. 
As to the length of the Newer Plistocene times a few hints should 
be given. The fresh water terraces, which in some localities are of 
considerable thickness, must have been a long time in forming. But 
how far these are synchronous with the marine, and how far the lat- 
ter are posterior to the former, it has been impossible thus far to de- 
. termine with accuracy. And as respects the two sections of the 
marine deposits there is still not a little doubt. The Leda clay has 
been usually regarded as a deep sea formation, since it holds pelagic 
specimens in small number. While Foraminifera, (to take what are 
considered as the most conclusive indications in this direction,) are 
characteristic of deep waters as a rule, they are yet occasionally 
found in those which are comparatively shallow, as, for instance, in 
