1886, | Geology and Paleontology. 965 
details which can be there studied to the best advantage. Much 
that is there revealed has already thrown new light upon the 
origin and life-history of metalliferous deposits, but I cannot now 
touch upon these topics.' The gigantic geyser-mounds are in 
themselves of marked interest, not only from their great size and 
external configurations, but also on account of their internal 
structure as proven by the excavations made in some of them for 
mining purposes. The American Belle, Grand Prize and other 
mines were opened directly in mounds of this nature, and (as in 
many other cases where only ordinary thermal springs probably 
existed) caverns were invariably entered after passing through an 
outer shell of considerable thickness. In nearly all of these some 
connection with the surface was traceable by following the tracks 
of woodchucks, which had utilized the passages as domiciles, 
In the caverns, which are sometimes of large dimensions, there is 
usually a deposit of sulphuretted ores, with allied minerals, with 
a very considerable amount of yellow and red material resulting 
from its oxidation and the production of carbonates. 
_No doubt much valuable information bearing directly upon the 
life-history of the geyser may yet be gathered from detailed 
Studies in this district. But little real exploration underground 
las yet been accomplished, and that small amount is but par- 
= tially known to those who can make the best use of it for scien- 
_ tific purposes. All that the writer has yet observed agrees in most 
2 €ssentials with what may be seen in the extinct subterranean 
Passages at Gardiner’s river, Wyoming, except that the metal- 
liferous deposits and the geyseritic relics are peculiar to the Red 
ountain area——Dr. Theo. B. Comstock, Champaign, Illinois. 
SCHLOSSER on CREODONTA AND PHENACODUS.2—Dr. Schlosser 
has attacked the problem of the Creodonta with his accus- 
tomed skill, and has thrown the additional light of his exten- 
šive acquaintance with mammalian anatomy on the subject. 
op et Seat A eee” fe ee See 
like him, of an order Bunotheria, but rather with Lydekker, 
of the order Carnivora. He does not regard them as an- 
Cestral to the Carnivora, but as having had a common ancestor 
with that order. This common ancestor he derives from hy- 
_ Pothetical Marsupialia with numerous temporary teeth. He ex- 
Cludes from the Creodonta the Hyznodontide and Muiacide, 
1884-86, now running (* Metallurgy of San Juan county Ores ”’); also 
per previously quoted in Trans. Am. Inst. M a 
Verhaltniss der Cope’schen Creodonta zu den übrigen Fleischfressern ; 
isches Jahrbuch 1886, p. 287, von Dr. Max. Schlosser. — ' 
