164 THE DEPTH AND MARINE DEPOSITS OF THE PACIFIC OCEAN, 
nation of a palagonitic tuff from Station 2 and of the peculiar Red Clay above 
referred to, from Station 4719, and these appear as an appendix to this paper. 
Throughout the abysmal area, quartz grains, when present, are rare, 
compared with their abundance in the terrigenous deposits close to shore, 
and it is very doubtful if any stratified rock has yet been discovered which 
can be regarded as the equivalent of any deposit now forming in the deep 
water far from continental land. It is extremely difficult to picture to one’s 
self how a continent, such as we understand the term, could ever have 
existed in the centre of any of the great ocean basins, which appear to be 
the most stable portions of the earth’s crust, while the continental areas, 
especially the border regions, are the most unstable. 
