348 THE CAUSES OF THE XI 
careful observations and soundings of the bottom 
of the Atlantic; and although, as we must all 
regret, that up to the present time that project has 
not succeeded, we have the satisfaction of knowing 
that it yielded some most remarkable results to 
science. The Atlantic Ocean had to be sounded 
right across, to depths of several miles in some 
places, and the nature of its bottom was carefully 
ascertained. Well, now, a space of about 1,000 
miles wide from east to west, and I do not exactly 
know how many from north to south, but at any 
rate 600 or 700 miles, was carefully examined, and 
it was found that over the whole of that immense 
area an excessively fine chalky mud is being 
deposited ; and this deposit is entirely made up of 
animals whose hard parts are deposited in this 
part of the ocean, and are doubtless gradually 
acquiring solidity and becoming metamorphosed 
into a chalky limestone. Thus, you see, it is quite 
possible in this way to preserve unmistakable 
records of animal and vegetable life. Whenever 
the sea-bottom, by some of those undulations of 
the earth’s crust that I have referred to, becomes 
up-heaved, and sections or borings are made, or 
pits are dug, then we become able to examine 
the contents and constituents of these ancient sea- 
bottoms, and find out what manner of animals 
lived at that period. 2 
Now it is a very important consideration in its- 
bearing on the completeness of the record, to” 
