Wyville Thomson—General Ocean Circulation. 357 
from no other source, and that it must be continually receiving 
new supplies, for it is overlaid by a band of colder water, tend- 
ing to mix with it by convection. 
It is, of course, possible that these warm currents may b 
ing; sometimes a group of very dark lines gives a marked 
ae Between the stronger blue lines 
m of closer lines ma 
Sheets of clear ice; the white intervening bands are the sections 
of layers of ice where the particles are not in such close contact 
—ice probably containing some air. 
€ stratification in all these icebergs is, I believe, originally 
horizontal and conformable, or very nearly so. In many, while 
melting and beating about in the sea, the strata become inclined 
at various angles, or vertical or even reversed; in many peey 
are traversed by faults, or twisted, or contorted, or displaced ; 
