of the United States. 37 
by beds of white sand, pebbles and porcelain clay. I am 
rather inclined to arrange the sand of New-Jersey in the 
same class; but future observations must determine this 
point. 
Philadelphia is built upon a plastic clay and sand forma-- 
tion; the sand is of variegated hues; clay, which is 
very pure, is found at thirty feet below the surface of the 
un ; 
At Cape Sable, in Maryland, vast beds of lignite are: 
found, containing amber, which has been described by Dr. 
Troost in the American Journal of Science. It is well 
known that the amber of Prussia is found in a similar situa- 
tion, and thus in distant parts of the world similar strata 
contain the same mineral substances; and the amber of the. 
Baltic has an ally and a brother in the formations of plastic 
= sand, and lignite, at Gay Head, Bordentown and Cape 
Die, po bse: F ie do eft yey 2 ett e: 
The clays of this formation abound in Florida; speci- 
mens are deposited in the cabinet of the Academy of Natu- 
ral Sciences in Philadelphia, from Escambia bay, seven 
miles above Pensacola, and from Mobile bay in Alabama. 
I am informed by Major Ware, who has travelled over 
great part of the southern frontier of the United States, that 
the plastic clay extends over several hundred square miles, 
In the tract of country which this embraces, in every exca- 
vation which the inhabitants make to obtain water, they dig 
up a fine dark red clay, which in some instances they use 
to paint their houses ; the surface is composed sometimes 
of the clays and sometimes of the sands of this formation. 
Another situation where it appears in a very conspicuous 
station, and with prominent characters, is at Chicasaw 
Bluffs and at Natchez, which have been described by Mr. 
uttall under the term alluvial, in his tour to the Arkansas. 
It also abounds in many other situations, and on a reference 
to Cleveland every locality which is noticed as affording 
