1864.| Waxuicn on the Atlantic Deep-sea Bed and its Inhabitants. 37 
for a later period, these earlier soundings were not barren of highly 
important results; for they enabled Professor Ehrenberg, on compa- 
rison of the material obtained from the bottom with that entering 
into the formation of chalk, to announce the extraordinary fact, that 
this rock is built up, atom by atom, of shells similar to those met 
with in such profusion along the bed of the ocean ; and further, 
that it must have been deposited under conditions similar to those 
now prevailing; thereby furnishing the clearest proof that the great 
forces which were in operation at the sea-bed countless ages ago, are 
in operation still; and will, in all probability, continue to be so 
through all time. 
We now arrive at the period when the survey of the sea-bed 
received a fresh and powerful impulse from the project of establishing 
communication between Hurope and America by means of a Telegra- 
phic Cable. With a view to ascertain the general contour and com- 
position of the portion of the Atlantic it was proposed to traverse, an 
expedition was sent by the Government of the United States, to sound 
from shore to shore. But unfortunately, the information elicited in 
the course of this survey was so vitiated by inaccuracies as to have in- 
duced the eminent officer, then in charge of the Hydrographic depart- 
ment at Washington, to pronounce it untrustworthy. A second 
expedition was accordingly equipped, under the auspices of the British 
Government. Of the accuracy of the depths recorded on this occasion 
there could be no doubt. But the intervals between the positions at 
which soundings were taken were so great, and the means of obtaining 
specimens of the bottom so imperfect, that, looking at the matter as 
we now do after the event, it seems impossible to regard the informa- 
tion elicited as in any degree adequate to meet the requirements of 
the enterprise for which the survey was undertaken.* 
It is true these soundings, as far as they went, indicated no extreme 
alternations of level along the course traversed. But on the other 
hand, nothing could be more hazardous than to assume, because a cer- 
tain degree of uniformity as to depth manifests itself at the isolated 
spots on which soundings were taken, that a like degree of uniformity 
must prevail over the wide intervening spaces. Of the spaces them- 
selves we know literally nothing. Nevertheless on these imperfect 
premises was it maintained, and by many persons believed, that the 
entire central tract of the Atlantic, instead of being characterized by 
variations of level and occasional areas of naked and perhaps rugged 
rock, such as we might expect to encounter here and there in a region 
SO extended, consists of a level plateau, the entire surface of which is 
covered by a soft stratum of mud, similar to that indicated by the 
earlier soundings. Now, it must be obvious to every one that, however 
steep a submerged declivity may be, unless the depth is ascertained at 
two or more consecutive points, the information elicited will be the 
same as if the sounding-machine had been dropped on the most perfect 
level. And accordingly, for aught these soundings have shown to the 
* To render this statement intelligible, it may be mentioned that along 1,300 
miles of the Mid-Atlantic Telegraph route, only forty-one soundings were > taken, 
the intervals varying between 32 and 71 seogtaphical miles. 
