PARK CITY, MINING DISTRICT, UTAH 451 
Dr. Girty, who has examined the faunas collected from it and pre- 
pared the list of species given below, states that 
“the fauna and horizon are those which in the Fortieth Parallel Survey Reports 
are called Permo-Carboniferous in the Wasatch and Uinta Mountains. The 
fauna consists almost exclusively of pelecypods, chiefly pectinoids, a few of 
which are described in the reports above referred to. With these exceptions the 
fauna was entirely new tome... .. It now seems probable that the fauna will 
be correlated with the Permian of the Grand Canyon section, and will prove to be 
in fact Paleozoic.’ 
The limestones and the peculiar calcareous sandstones are rich 
in organic remains. In their characteristic and distinctive fauna 
three forms are almost universally present, Myalina, aviculipecten, 
and lingula, while Spirifers and Dentalia are usually present in 
faunas from limestones. The first three forms are found throughout 
the Thaynes formation, including the highest and lowest members, 
and are indicative of this formation. Pentacrinus, which also serves 
as a valuable index, is limited to the part lying above the “mid-red” 
shale. The following species in the list submitted have been identi- 
fied by Dr. Girty: 
PARTIAL List oF PERMIAN FossILs IDENTIFIED IN PARK City DISTRICT 
Pentacrinus sp. Aviculipecten curticardinalis 
Myalina permiana Aviculipecten Weberensis 
Myalina aviculoides Aviculipecten parvulus 
Aviculipecten occidaneus 
In addition to these recognized forms, Dr. Girty states that the 
collections from this formation in the Park City District include 
fully thirty new species, and that nearly as many more have been 
found outside the district. 
In its stratigraphic relations this formation is intimately related 
to the two inclosing shale formations, in that during its deposition 
the same conditions frequently prevailed as during their deposition. 
No great unconformity either above or below was noted, though a 
slight unconformity by erosion was observed at one horizon within 
this formation, and others doubtless exist. 
The persistence of certain members of the Thaynes formation 
is noteworthy. Thus the “mid-red” shale, with a thickness of only 
t Extract from report on collections submitted by the writer for identification by 
Dr. Girty, Paleontologist, U. S. Geological Survey, dated August 11, 1903. 
