846 
Rocks and gravel and sand, together with 
mud and silt, if near the mouth of a river, 
would succeed each other. The surface 
might be broken into rocky pinnacles and 
caverns, water-worn in fantastic shapes in 
the region of a rocky coast ; or, if the coast 
be low and sandy, there might be a per- 
fectly even and gradual slope from the 
shore to a depth of 150 or perhaps 200 
fathoms. 
This slope, covered with continental dé- 
bris, is known as the ‘continental slope,’ 
and is very apt to be more uneven and 
broken in its topography and to support a 
more luxuriant fauna than any other part 
of the sea bottom. Beyond the continental 
slope the descent becomes more abrupt, lead- 
ing down to adepth of 1,500 fathoms or more. 
The bottom samples will now take on a 
distinetly different character, being com- 
posed of a grayish mud. If a little of this 
is examined under a microscope, it will be 
found to be made up of countless millions 
of the tests of Globigerina and other uni- 
cellular animals. Not a single thimble- 
ful of this mud is devoid of its hosts of 
skeletons. This wet and slimy bottom soil 
is known the world over as ‘ Globigerina 
ooze,’ and it covers the ocean floor for many 
millions of square miles. 
In a line of dredgings made by the 
Challenger from Teneriffe to Sombrero, tak- 
ing in the widest part of the Atlantic, 
about 710 miles were found to be covered 
with Globigerina ooze, which was found in 
characteristic form from a depth of 1,525 
to one of 2,220 fathoms. Beyond the latter 
depth the bottom was of a distinctly dif- 
ferent character, changing to an extremely 
fine-grained reddish-brown mud, oily to the 
feel. It is so finely divided that it takes 
many hours to settle when mixed in a glass 
of water. This is known among oceanog- 
raphers as ‘red clay,’ and is supposed to 
be derived almost exclusively from two 
widely different sources : 
SCIENCE. 
[N.S. Von. XIII. No. 335. 
First : The residue of the innumerable 
hosts of pelagic animals remaining after 
their caleareous skeletons have been dis- 
solved in sea water. 
Second : Pumice and volcanic dust, either 
from submarine upheavals or from the at- 
mosphere. From either or both of these 
sources the accumulation of the red clay 
must have been almost infinitely slow, tak- 
ing perhaps millions of years to deposit a 
few inches in thickness on the ocean floor. 
This sort of bottom deposit is of much 
greater extent than either of the others, 
and is supposed to cover about one-half of 
the sea bottom, an area greater than the 
total land surface of the globe. 
It can easily be conceived that no stretch 
of the land surface can compare in dreary 
monotony with those awful solitudes of the 
Globigerina ooze and the red clay. Even if 
illuminated by the sun’s rays, they would 
be forbidding and dreary beyond compare. 
Resting immediately upon the bottom al- 
ready described is a layer of unknown 
depth of a flocculent material that is of in- 
calculable importance in our discussion. 
When first discovered this substance, ow- 
ing to its strange movements in alcohol, 
was supposed to be alive, and was described 
by Huxley under the name of Bathybius, 
and considered as a sort of primordial or- 
ganism from which the entire life of the 
globe may have originated. Bathybius, how- 
ever, was doomed to be regarded as one of 
the colossal jokes of science, and a thorn in 
the flesh of its describers. 
But, after all, it is now thought that the 
much-derided Bathybius is fully as impor- 
tant as claimed by Huxley, but in another 
way. It is not alive, to be sure, but still it 
is organic, consisting of the partially de- 
composed remains of the pelagic animals, 
such as Globigerina and other forms already 
referred to. These have died near the sur- 
face, and have gradually but surely found 
their way to the bottom, where they remain 
