10 
The preceding diagram represents the series so far as it has 
been developed in this country. In Europe, the Upper Terti- 
ary is not unfrequently alternated with beds of fresh water 
shells, mostly attributable to a lacustrine origin No such ex- 
amples have yet been noticed on this side the Atlantic. Again, 
the European Tertiary is based upon the Chalk formation ; but 
although in the United States, no Ch lk, mineralogically speak- 
ing, has been observed, Dr. Morton has shewn, in the most 
satisfactory manner, that we possess its Geological equivalent 
in the marl of New Jersey, Delaware, &c. which is in fact 
contemporaneous with the Lower Chalk or Ferruginous Sand 
formation of Europe ; the upper mass, or Chalk of commerce, 
being wanting. 
These formations, collectively, form the Atlantic margin of 
the United States, from Sandy Hook, in New Jersey, to the 
peninsula of Florida, from whence they skirt the Gulf of Mex- 
ico to the waters of the Mississippi. Of the Geology of the 
region west of this, very little is known; but on Red River, shells 
of the Ferruginous Sand formation were discovered by Mr. Nut- 
tal during his hazardous journey through the inhospitable wilds 
of the Arkansas territory, led solely by the love of Science, 
to which he had nearly fallen a martyr. 
This southern portion appears to occupy a much broader 
space than is observable in the northern sections, but the order 
of position is of course the same in all. The same formations 
appear to have an insulated existence in Martha’s Vineyard, 
the Elizabeth Island, Long Island, &c. on the coasts of the 
the Eastern States. The tract to which we allude is called 
Alluvial on Mr. Maclure’s geological map of the United States; 
and although the name is incorrect, the geographical bounda- 
ries there given are sufficiently accurate for general purposes. 
Let us now take a glance at the several subdivisions of the 
Tertiary class, together with the Alluvial and Diluvial deposits 
which are frequently found overlying them. 
Alluvium. This name is applied to all deposits derived 
from causes now in operation. Such are the accumulations of 
mud and other debris at the mouths and along the courses of 
rivers; the drifting sands of the sea coast; peat bogs, &c. &c. 
Of all these circumstances we see numerous examples through- 
out the Atlantic margin of the United States, and especially in 
