1881. ] Geology and Paleontnogy 339 
Under the low grade ore bed just described, comes in a soft, 
white feldspathic porphyry, which in this vicinity usually averages 
about fifty feet thick, although I know of a point about one mile 
east, where it was found to be over two hundred feet thick. This 
white porphyry lies immediately above the iron with which and 
in which the ore bodies are found. A study of the accompanying 
diagrams will aid in gaining a clear idea of the lay of the different 
formations, 
Enough development has already been accomplished at numer- 
ous points to prove that the ore body uncovered in the Denver- 
City discovery shaft belongs to the Fryer hill deposit, and it is 
equally certain that such ore deposit with a few local waves, and 
also possible slight faults, continues in a practically unbroken dip 
from the extreme western workings of the Chrysolite group, in 
an easterly direction for a distance of over four thousand feet, to 
“Yankee Hill Contact.” This break corresponds very nearly to . 
the fault which separates Carbonate hill from Iron hill, and which 
fault is better understood, as the foot wall of the ore bodies on 
those hills is a heavy ledge of limestone undoubtedly, in place; 
whereas the foot wall of the present Fryer hill bodies is generally 
a layer of true quartzite, or metamorphosed sandstone, which in 
turn lies upon a hard white, silicious porphyry, similar to that 
which overlies the whole of the Carbonate and Iron hill ore 
bodies. In places this quartzite is wanting, in which case the 
mineral lies upon the hard white porphyry. This porphyry has 
not yet been passed through by any of the shafts so far sunk upon 
. Fryer hill, and what underlies it is still an unsolved problem. I 
will venture to predict, however, that other and possibly larger ore 
bodies than those now being worked are yet to be found in place, 
with lime as a foot wall, under this porphyry; and such bodies 
will probably also be richer in lead, if not in silver, as is the case 
with the ore bodies found on lime in other portions of the camp. 
This, at least, is a matter which should be proved by sinking 
= Vtipacets shafts on Fryer hill to the granite bed rock—W. G. 
hedd. 
memoir. Mr. Filhol shows that in this genus, the foramina of the ; 
base of the skull characteristic of the Wimravide and Cryptoproc- 
tide, are all present. These are the two alisphenoids, the post-~ 
glenoid, and the distinct carotid and condyloid.. These foramina — 
