Geology and Natural History. 598 
level, excepting where worn into deep gulches by the oe 
streams. ‘lhe river has cut through to a depth of over ote 
hose near streams in the north of England that cut anioagh 
thick beds of bowlder clay. The evidences of glacial action be- 
tween Depilto and Ocotal were, with one exception, as clear as in 
any Welsh or Highland valley. "There were the same rounded and 
moothed masses of rock, the same moraine-like accumulations of 
siehtratified sand and gravel, the same pe dori bowlders that 
coul ne traced to parent rocks several miles distant 
“The transported boulders, near Ocotal, are about three 
thousand feet above the sea, those near Libatad ‘about two thou- 
sand fee 
Mr. Belt infers, from the facts, that the ice of the Glacial era 
stretched on uninterruptedly from the northern regions of North 
America throug entral America, and probably over South 
America. But observers have shown that the glacial phenomena 
occurring on a grand scale about the higher mountains of Califor- 
nia and of the summit region of the Rocky Mountains, within the 
United States, are those of /ocal glaciers, and that there is there 
no northern drift. This being so, it is certain that the facts de- 
scribed by Mr. Bent indicate the existence iat of local glaciers 
—those of the mountains of northern Nicaragua ey are stil 
of very great interest, as they pa ea ‘cit more southern limit in 
North America to the local viaian of the Glacial era see — 
been before suspected. 
._ Geological Structure of the Alps.—In the Geneva Archives es 
structure being often ee * that observed in the porphy- 
ritic aod oe 
tinetly ; the granite 1 sii Sans Sabbah it often passes into oi 
former ‘by insensible gradations, and thus evinces a common 0 
