288 
IMPEEFEOTION OF THE 
Chap. IX. 
over the whole world, the land and the water has been 
peopled by hosts of living forms. What an infinite 
number of generations, which the mind cannot grasp, 
must have succeeded each other in the long roll of 
years! Now turn to our richest geological museums, 
and what a paltry display we behold I 
On the poorness of our Palaeontological collections .— 
That our palaeontological collections are very imperfect, 
is admitted by every one. The remark of that admir¬ 
able palaeontologist, the late Edward Forbes, should not 
be forgotten, namely, that numbers of our fossil species 
are known and named from single and often broken 
specimens, or from a few specimens collected on some 
one spot. Only a small portion of the surface of the 
earth has been geologically explored, and no part with 
sufficient care, as the important discoveries made every 
year in Europe prove. No organism wholly soft can be 
preserved. Shells and bones will decay and disappear 
when left on the bottom of the sea, where sediment is 
not accumulating. I believe we are continually taking 
a most erroneous view, when we tacitly admit to our¬ 
selves that sediment is being deposited over nearly the 
whole bed of the sea, at a rate sufficiently quick to 
embed and preserve fossil remains. Throughout an 
enormously large proportion of the ocean, the bright 
blue tint of the water bespeaks its purity. The many 
cases on record of a formation conformably covered, 
after an enormous interval of time, by another and 
later formation, without the underlying bed having 
suffered in the interval any wear and tear, seem ex¬ 
plicable only on the view of the bottom of the sea not 
rarely lying for ages in an unaltered condition. The 
remains which do become embedded, if in sand or gravel, 
will when the beds are upraised generally be dissolved 
