674 WHITMAN CROSS 
teristic Aubrey forms are, however, lacking (Productus occidentalis, P. Ivesi, 
Allerisma capax, etc.). This fauna is more like that of the Weber quartzite 
formation of Bingham, Utah, which, at the present time, I provisionally correlate 
with the Aubrey. Newberry’s list making the necessary synonymic changes 
is almost identical with Powell’s, as far as it goes. ‘The collection is smaller, 
and, of course, lacks many forms which might be obtained on further search. 
Considering the Powell and Newberry collections together, it is notable that 
they contain a considerable number of species which may be called distinctive 
western types, as compared with the Pennsylvanian fauna of Colorado and of 
the Mississippi Valley. ‘These species are marked by an asterisk following the 
names in the list. In some cases nothing at all closely related to the types indi- 
cated is known from the region to the east. In other instances there are more 
or less similar species known which are not yet regarded as identical with western 
forms, although they may prove to be so. 
The collections from Moab consist entirely of typical Pennsylvanian species, 
lacking the forms specified as characteristic of the far western areas. The dis- 
tinctly Pennsylvanian forms found at the junction of the Green and the Grand 
occur, however, at Moab. The Sindbad Valley fauna is very closely related to 
that from Moab. 
In view of the fact that none of these collections can be considered as exhaus- 
tive for the localities, numerical comparisons are more or less untrustworthy; 
yet the table brings out certain contrasts or resemblances which seem worthy of 
note. Out of 42 species represented in the Powell and Newberry collections 
but 9 have been found at Moab, or in Sindbad Valley, while out of 43 species 
obtained in these latter localities 29 are known from the Pennsylvanian rocks 
of southwestern or central Colorado. 
On the basis of the fossil evidence alone there can be no hesitation in con- 
sidering the Moab and Sindbad Valley sections as belonging to the Hermosa 
formation rather than to the Aubrey, as represented in the lower Grand River 
Valley. 
The strong similarity which Mr. Girty has pointed out between 
known faunas of the Moab district and of Sindbad Valley to that of the 
Hermosa formation of Colorado, and the contrast with the faunas 
collected by Newberry and Powell, require some explanation. 
As stated on p. 668 the collection made by Newberry was obtained 
less than to miles below Moab, if the Cafion Colorado of recent maps 
is the same as the canyon of that name through which Newberry 
descended to Grand River. If he reached Grand River as near to 
the junction of the Green as he himself supposed, the locality of New- 
berry’s collection was still in all probability not more than 25 miles 
from Moab. One explanation of the difference between the Moab 
