98 Mr. Maclure on the Geology of part of N. America. 
Ant. Ul.—Some speculative conjectures on the probable 
changes that may have taken place in the Geology of the 
~ Continent of North-America east of the Stoney Moun- 
_ tains ; by Wittiam Macture, Esq. President of Acade- 
my of Natural Sciences, at Philadelphia, and of the 
American Geological. Society. 
a 
es of Vulcanic, (Volcanic?) Alluvial, Secondary, and Trans- 
‘ 
on plains that are nearly horizontal, we are tempted to con- 
jecture that the earth took that form from the depositions 
from water, &c. &c. &e. 
The continent of North-America, east of the stoney moun- 
tains consists of a ridge of primitive mountains, springing out 
of the great northern primitive formations, covered to. the 
east and south-east by extensive beds of alluvial, apparently 
the depositions of the ocean, and on the west side overlayed 
by Travsition and Secondary, filling the immense basin 
through which the Mississippi now runs with all its attend- 
ant streams. 
