Editorial Comment. 381 
grit, or the later Upper Helderberg faunas. Near the top of 
the Corniferous limestone is a remarkable layer composed of 
minute gypsum crystals in an amorphous gypsum base. After 
the appearance of the fauna of the Marcellus shales, there was 
an abrupt return, for a brief period, of many of the Cornifer- 
ous species, and when these had disappeared and a character- 
istic Marcellus fauna had again held sway for a considerable 
time, there was an abrupt appearance of a highly developed 
Hamilton shales fauna (Stafford limestone) which, again, 
soon retreated, leaving the field to the Marcellus species and 
their bituminous environment. The influences of the Marcel- 
lus conditions, both physical and organic, are carried far up- 
ward beyond their usual limit, and the return of the Hamil- 
ton fauna, together with the elimination of the bituminous 
matter from the sediments, is a very gradual process. Through- 
out the entire section the range and individual development 
of each species are carefully recorded. Mr. Luther's report is 
supplemented by some paleontological notes and descriptions 
by J. M. Clarke. 
The real geological importance of such deep shafts can not 
be overestimated as the results derived therefrom have a 
mathematical precision. We learn that the preparations for 
the monster exposition at Paris in 1900 are contemplating a 
proposition from deputy M. Paschal Grousset to put down a 
shaft on the exposition grounds 1,500 meters, or about a mile, 
in depth. If such an exploit were feasible (the increase of 
temperature downward would probably curtail it), it would 
certainly be a most profitable venture on behalf of exact strat- 
igraphy and terrestrial physics, although it might not settle 
the questions which M. Grousset wishes to elucidate and 
which are thus stated by a special correspondent: "(1) 
Whether the theory of the central fire of the earth be fact or 
fiction, (2) whether this source of internal heat, if such exist, 
be accessible or utilizable, (3) whether or not the sub-soil of 
Paris serves as a roof to a vast ocean of soft water." The 
language is as bold as the proposition, and if such amazing 
conditions exist beneath Paris, it is certainly high time the 
Parisians did somethin"- about it. 
