. 
W. Hopkins on Changes of Climate. 337 
the glacial period. But there is another mode in which the di- 
version of this great current may, as it appears to me, have been 
eflected, and to which I would especially direct the attention of 
geologists. 
33. On the west of the continent of North America, a contin- 
lots and lofty range of mountains, the Rocky Mountains, ex- 
tends from Mexico to the Arctic Sea. Another, but far less lofty 
chain, the Allechanies, runs parallel to the eastern coast from near 
the Gulf of Mexico to the St. Lawrence. The great valley 
ue 
along the eastern base of the Rocky Mountaiss. 
The Gulf-stream, flowing through the Straits of Bahama, and 
afterwards, in its northeastern direction, towards the North Sea 
and the coasts of Europe, is a current reflected from the shores | 
of the Gulf of Mexico in consequence of the impossibility of its 
fhtinning the northwestern course by which it reaches the 
~ Sut in the case now su 
* See Sir J hn Ri , “Qn some points of the Physical Geology of 
North America, ea,” cao pookd . Geol. Soc. 1851, vol. vii, p. 212. | 
- Stcox> Seutes, Vol. XV, No. 45.—May, 1853. Ab Sai kd 
