On the Leriiary Formaiions of the Hudson. 229 
as forming a level plain of some extent, on which the milage 
and several gentlemen’s country seats are situate 
lieve a plain of similar elevation, may be traced in many sins 
parts, bordering on the Hudson. 
Between Hyde Park and Rhinebeck, are extensive depo- 
sitions of clay. 
Albany is built on the clay marl formation, and in this 
fespect resembles London. The ground is traversed by nu- 
merous ravines, In the vicinity, the cascades of Arno and 
Tivoli, and the rapids of Norman Kill, which every one who 
sees will admire, are caused by the torrents wearing away the 
higher strata, until they arrive at the solid strata of the transi- 
tion slate. 
At Greenbush is an extensive formation of the adhesive 
slate. _Dr.3T. Romeyn Beck has deposited sreine in the 
Cabinet of the Lyceum of Natural History, in in Albany. 
a Tro oY the clay marl is abundant, and contains: fossil 
wood he plain above the city, from whence there is a fine 
distant view of the falls of the ohawk, is composed of diln- 
vial debris. The height of the formation at this place is pro- 
bably the same as at Hyde Park and Marlborough. 6 
strata, in ne vicinity, have been described by Mr. Eaton in 
his Index to the Geology of the Northern States. 
At Sebsecsady the same formations are visible; they also 
form the whole tract of country, between that city and Al- 
“These strata may undoubtedly be classed with the ter- 
ay clays of Europe, but they vary in some particulars. 
e London clay contains numerous fossil shells, and the 
Bhatt of extinct animals,. but pone have hitherto been found, 
in the clay marl on the North riv , 
From the large depositions of aaheave Fa they agree 
more precisely with the formations at Mont Martre, near 
Paris, where there are alternating strata of “this mineral, and 
clay marl transition. 
"he menilite has not yet been found on the shores of the 
Hudson, although this is a position where we may expectit to 
be pat 
28 Broadway, New-York. 
