March Oy 1 S82 |P> 
NATURE 
435 
so readily that the fluid should pass again into a solid 
centre. Another formidable difficulty is that a subter- 
ranean ocean must be subject to tides, as much as the 
sea would be though covered by ice. This is passed over 
somewhat lightly with the suggestion that viscosity may 
be sufficient to obscure all tidal phenomena. Doubtless, 
too, other difficulties will start up for which it may not 
be easy to find a solution. But every theory is sure to 
present difficulties. Time must show whether they mul- 
tiply or die away. 
One or two points do seem to emerge from this assem- 
blage of calculations as fairly clear, and established on 
tolerably firm foundations. Such,are, that contraction of 
the earth by cooling is inadequate to the production of its 
greater inequalities. The earth cannot be a mass quite 
so homogeneous as on the theory of having coolec rrom 
a perfect fluid it is often assumed to be. There must be 
subterranean irregularities of density. Besides these, the 
phenomena of volcanoes seems to be explained best, as 
yet, by the existence of vapours and gases in intimate 
mixture with the materials below its crust. And a sub- 
stratum plastic, if not fluid, will account for many facts 
which are ordinarily very perplexing. But, to quote from 
a striking quotation made in the volume itself, “ Of all 
known regions of the Universe the most unsafe to reason 
about is that which is beneath our feet.” E.) HIEe 
LERBERS 1O THE EDITOR 
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Vignettes from Nature 
ANxrouS that popular scientific literature, especially that 
which deals with the Evolution-doctrine, should be strictly accu- 
rate in its facés, I would ask—in no unfriendly spirit—whether 
Mr. Grant Allen and Mr. Wallace have fully informed them- 
selves upon each of the several positions taken in the paragraph 
cited with approval by Mr. Wallace (in the last number of 
NATURE, p. 381) from Mr. Grant Allen’s ‘‘ Vignettes,” referring 
to the dimensions of the largest animals now existing, as com- 
pared with those of the faunz of past epechs, 
1. It is asserted that ‘‘no known extinct animal was as large 
as some of our modern Whales.” When, some thirty years ago, 
I visited the so-called ‘‘coprolite” pits in the Suffolk crag, I 
was astonished at the multitude of the ivory-like ‘‘ear-bones” of 
whales found in a certain group of them; which were described 
by Prof. Owen, and compared with those of existing Balenide, 
in his ‘‘ Fossil Mammals of Great Britain.” From the fragments 
of gigantic ribs and vertebree which I then saw at Felixstowe, I 
should certainly suppose the extinct whales they represent (which 
Prof. Owen regards as of Eocene age) to have been fully as 
large as those of the present time. 
I would ask, further, whether sufficient acccunt has been 
taken, in the statement just cited, of the most gigantic types of 
Reptilian Mesozoic life? Any one who has placed himself by the 
side of the huge bones of the Cetiosawrus which form sucha con- 
spicuous feature in the Oxford Museum, must, I think, be dis- 
posed to regard the animal there represented as having probably 
at least equalled the whale in éz/%, though very likely not in 
length. And even this colossal reptile must have been far 
exceeded ir dimensions by the A¢/antosaurus montanus described 
by Prof. Marsh from the Wealden of Colorado. I would respect- 
fully ask the authors, therefore, whether they are prepared to 
show that such an estimate is fallacious. 
2. Having been led to believe, by all I have seen, heard, and 
read, that the orvdivary bulk of our existing Elephants (I do not 
speak of exceptional ‘‘ Jumboes”’) was considerably exceeded 
by that of the Mammoth and Mastodon—the former surpassing 
them in hezghz (see the comparetive mea‘ urements given by Prof. 
Owen, of. cit.), and the latter in /ength of bedy, I cannot but feel 
surprised that Mr. Grant Allen should speak of elephants ‘‘as 
having been increasing in size from the earliest epoch of their - 
appearance to the present day’’; still more, that Mr. Wallace 
should endorse the statement. Of course I] shall at once bow to 
the superior knowledge of the latter most distinguished zoolo- 
gist, when he refers me to trustworthy measurements in support 
of his position. 
3. I can speak with more confidence in regard to the relative 
size of extinct Sharks, none of which, in the judgment of Mr, 
Grant Allen and Mr, Wallace, surpassed the forty-feet sharks of 
the present time. For I have now before mea tooth of a fossil 
shark (found in one of the before-mentioned ‘‘ coprolite pits”’) of 
pretty regular triangular form, measuring fous inches in length, 
three inches across the base, and seven-eighths of an inch in 
thickness between its flat surface and the most protuberant part 
of its conyex surface ; and I have seen others much larger, the 
length of some being said to range to s7x inches. Now when I 
brought this tooth home, I took an early opportunity of com- 
paring it with the largest teeth of existing sharks that I cculd 
find in the briti-h and Hunterian Museums, and found these to 
be pigmies by comparison. Unless, therefore, I can be referred 
to some fre:h source of information, I must continue to believe 
(face Mr. Grant Allen and Mr. Wallace) that some of tke older 
sharks were far larger than any of which we have any knowledge 
at present. 
4. Is it clear that Z>7dacna is the largest known Mollusk ? 
I should have thought it exceeded by the gigantic Ammonitide, 
the largest specimens of which are not always to be found in 
museums ; for I have seen one at Redcar (whose diameter I am 
afraid to state from memory, for fear of exaggeration) so 
massive that no one had undertaken the task of removing it. 
5. No mention is made of Cyestacca, though I should have 
thought that important class worthy of notice. I would ask 
where any existing crustacean types are to be found, that surpass 
in size the gigantic u7)'pfevid@ or even the largest 77z/odites. 
6. Of the Foraminifera, one of the most important classes in 
the whole animal kingdom for the share it has taken in the 
formation of our limestone rocks, I venture to speak with some 
special knowledge. The largest examples of this group known 
to us at the present time are the Op ditolites and Cycloclypeus, 
The former is a very widely diffused type, but only under 
peculiar local circumstances exceeds an inch in diameter, or one- 
tenth of an inch in thickness ; the latter is (so far as 1 am yet 
aware) restricted to one locality, and, though attaining the large 
diameter of 23 inches, is scarcely thicker than an ordinary card. If 
these be compared with the massive Ammulites and Orbitoides, 
of which the vast A’wmu/itic limestones are composed, the 
advantage will be found clearly on the side of the latter. 
But, in conclusion, I think it will be conceded that in estimating 
the general dimensions of a Faura, we must take into account not 
merely the s7ze of its largest animals, but the range oftheir dis- 
tribution ; and I would ask Mr. Wallace (whose knowledge of 
this subject no one appreciates more fully than myself) whether 
this consideration has been duly weighed by him. Our existing 
colossal land mammals (elephants, giraffes, rhinoceroses, and 
hippopotamuses) are limited to the tropical and sub-tropical - 
regions of the Old Would ; while the great American continent is 
entirely destitute of them. Let this state of things be compared 
with the former extension of the Mastcdon! and Mammoth 
through North America (which had for its own also the gigantic 
Brontotheride), as well as over Europe and Northern Asia ; and 
the nearly equal range of the Rhinoceros and Hippopotamus (some 
species of all which seem to have lived contemporaneously during 
the Quaternary Period) ; whilst at the same time the wide area 
of South America was tenanted by another Mastcdon, as well as 
by the colossal Sloths. There can be no reason to suppose again 
that the great Balzenidze were less abundant during the later 
Tertiary and Quaternary epochs, than they were either previously 
or subsequently. And if the evidence of the abundance of some 
of the colossal land- Mammals—afforded by the vast accumulation 
t That the Mastodon, though it appeared much earlier than the Mammoth 
in the Old World, continued to exist in the New during the Quaternary 
period, is now, I believe, generally admitted. I myself, at the request of 
Dr. Warren, examined the contents of the well-preserved specimen obtained 
by him, and found therein twigs quite fresh encugh for the microscopic 
recognition of their Coniferous structure; and Prof. Asa Gray told me last 
summer that he could clearly identify them with a well-known existing type. 
