GEOLOGY 
77 
lations, Further observations on these formations are desirable. The 
occurrence of blown sands, the origin of these accumulations, and the 
peculiar ridges they assume, usually at right angles, but in some remark¬ 
able cases parallel to the prevailing winds, are questions deserving of 
additional elucidation. 
Early History of Man in Tropical Climates .—Very little has been dis¬ 
covered as to the races of men formerly inhabiting tropical regions. It is 
evident that a race unacquainted with fire could only have existed in a 
country where suitable food was procurable throughout the year, and 
this must have been in a region possessing a climate like that found in 
parts of the tropics at the present day. It is possible that an investi¬ 
gation of the cave deposits in the tropics may throw some light on this 
subject. “ Kitchen middens/ 5 as they are termed—the mounds that have 
once been the refuse heaps of human habitations—are also worthy of 
careful examination. 
Permanence of Ocean-Basins .—"Within the last few years some geologists 
have adopted the theory that all the deep-sea area has been the same 
from the earliest geological times, and that the distinction between the 
depressions occupied by the oceans and the remaining undepressed portion 
of the earth’s crust, constituting the continents and the shallow seas around 
their coasts, is permanent. This view is very far from being universally 
or even generally accepted amongst geologists, although many who 
hesitate to accept the theory as a whole admit that parts of the oceans 
may have been depressions since the earth’s crust was first consolidated. 
The argument on both sides depends upon theories to which travellers 
can contribute but little except by observations on the geology, fauna, 
and flora of oceanic islands, and by the investigation of coral-reefs and 
especially of atolls. In ranges of hills or mountains near the coasts both 
of continents and islands and in all tracts where evidence of recent 
elevation exists, search should be made for deep-sea deposits. These are 
fine calcareous or argillaceous beds, often containing small Foraminifera 
or Kadiolaria, which, however, are generally extremely minute, and require 
microscopical examination for detection. If any beds of consolidated 
calcareous or siliceous ooze or especially if red or grey clay (in older 
rocks, slate, or even quartzite) be found associated with pelagic deposits, 
such as coral limestone, a few small fragments of the beds should 
always be brought away for examination^ and any distinct fossil remains 
