TERTIARY. 
131 
of the denudation which they have suffered; for like the non-fossiliferous slates, lithological 
characters are quite insufficient for their designation. The clay to which particular reference 
is made, is that which is known as the Albany clay, or that which lines the shores of the 
Hudson for a long distance, and which in fact is connected to, or continuous with, the clays 
of the valley of Champlain. But as this formation, the moment it leaves the valley of the 
lake, furnishes no fossils, it becomes, when considered by itself, an enigmatical mass ; con¬ 
nected, however, as it evidently is, with the tertiary of Champlain, its characters and age are 
at once brought out, and we learn for the first time that it is one of the most recent of our 
marine formations. Other facts throw an interest over it, which is wanting in other cases, 
even the more extensive ; they are those connected with the period and circumstances under 
which it was deposited ; first, it succeeded the period when the rocks of the valley of Cham¬ 
plain were grooved and scored, a period which may have been stormy, unsettled and fluc¬ 
tuating. To this succeeded a period of repose, when the argillaceous matter of this formation 
was quietly deposited, the lower portions of which formed rapidly from the great abundance 
of this matter in its waters, so much so as to prevent the existence of even molluscous ani¬ 
mals. After a while, the turbidness so far diminished that animals became inhabitants of the 
waters, a period marked by the appearance of sand. These animals were rapidly extending 
themselves in different directions, when suddenly the whole region was uplifted and raised 
above the sea. During this period, boulders were evidently transported either by shore ice, 
or on icebergs, and were frequently deposited in the midst of the beds and congregations of 
these living animals, but did not at all interfere with their existence. Thus, at Beauport near 
Quebec, small water-worn rocks are found in the midst of the fossils, and in numerous 
places single boulders are dug out of this clay in the process of excavation for the purposes 
in which it is employed, though they are by no means numerous. It has, however, been 
observed by some geologists, that there is often a mass of drift beneath the tertiary. I have 
not, however, seen those localities cited in proof, but have been disposed to regard them as 
belonging to another mass, and not as beneath the true tertiary of Lake Champlain; they 
belong rather to the drift, in which beds of clay may often be found holding a position above 
a mass of drifted rocks and stones. Such masses are very common in the primary and 
mountainous districts of New-England ; they are always insulated, and never continuous but 
for a limited , extent. They are found reposing on the sides of hills, and in the valleys ; and 
the boulders in them are very numerous, and they contain but a small proportion of carbo¬ 
nate of lime. 
I have stated that the upper portion of the tertiary has been removed ; and that in carrying 
away its fossils, the currents which swept over it removed also the criteria by which to judge 
of its age, and of the medium in which it was deposited, whether of marine or of lacustrine 
origin. In the place occupied by this removed portion, we often find the latest drift. Some 
difference of opinion, however, has been expressed in relation to this, viz. that it has not been 
transported by a forcible current, but is the result of slow transportation from neighboring 
hills. Now, if there were not clear evidences of a rapid abrasion of the upper part of this 
