RECONNAISSANCE IN COLORADO AND UTAH 667 
and without difficulty. A few miles above the point at which we 
left Grand River, Boutwell found a section of “‘light pinkish-purple, 
shaly sandstones which include coarse cross-bedded sandstones and 
conglomerates with well-rounded granite and porphyry pebbles”’ 
under a massive sandstone which corresponds to the Vermilion Cliff 
(1). ‘These might belong to the section resting on the Pennsylvanian 
beds near Moab, but seem much more probably to represent strata 
above the gypsiferous beds and roughly equivalent to those seen on 
West Creek. 
Comparing the strata known on Grand River between the Dolores 
base and the Pennsylvanian limestones with the Cutler formation 
(Permian ?) of the San Juan Mountains it is clear that the gypsiferous 
part of the series has no similar representative in the mountain district. 
If such beds ever existed in the San Juan region, they were removed 
prior to the deposition of the saurian conglomerate, and this does 
not seem at all unlikely, for gypsiferous beds are known in the Paleo- 
zoic red beds of northwestern Colorado, as reported by Peale (29). 
The grits and conglomerates of West Creek are so near their source 
that they differ from the Cutler beds in being much coarser and more 
strongly arkose, but the section seen on Grand River and Fisher 
Creek certainly resembles in lithologic character the Cutler beds of 
the Uncompahgre Valley below Ouray, and appears to occupy the 
same stratigraphic position. 
The Cutler formation and the pre-Dolores red-bed strata of Grand 
River clearly correspond to the lower part of Powell’s Shinarump 
Group, that is, to the ‘‘ Permo-Carboniferous” of the Wasatch and 
Uinta Mountains, according to the nomenclature of the Fortieth 
Parallel Survey, or to the Permian of Dutton, in the Grand Canyon 
monograph. Fossils indicating a Permian or Permo-Pennsylvanian 
age were found by the Fortieth Parallel geologists in the Wasatch 
Mountains and by Walcott in the Kanab Valley of northern Arizona. 
The apparent absence of fossils in most localities where these beds 
have been examined is no doubt due to the fact that they are mainly 
continental deposits, an origin indicated by their texture. | 
The site of one of the land masses from which these deposits were 
derived is shown by the relations existing on West Creek. Peale 
assumed that this plateau belonged to an island extending eastward 
