658 WHITMAN CROSS 
embodied the result in a paper which will appear in this journal 
during the current year. A brief summary of certain facts and con- 
clusions will suffice in this place. 
The Shinarump conglomerate, named by Powell (31), is in the 
midst of a series of strata well shown to the north of the Grand Canyon 
called the Shinarump Group by Powell (33), who believed the whole 
to be Triassic. Gilbert (14), Walcott (37 and 38), and Dutton (9) 
have observed unconformity by erosion below the conglomerate, 
while Walcott obtained Permian fossils in the lower part of the group 
in the typical Kanab section, and since that discovery geologists gener- 
ally have adopted Walcott’s view that the Shinarump conglomerate 
should be taken as the base of the Trias of the Plateau Province. 
The correspondence in stratigraphic position between the Shina- 
rump and the lower conglomerate of the Dolores formation naturally 
suggests their identity and I am strongly inclined to believe that they 
will ultimately be found to occur at the same horizon. ‘There are, 
however, some discrepancies and apparent differences between the 
observed sections that must be explained before this opinion can be 
accepted. 
It has been asserted by Powell and Dutton in almost unqualified 
terms that the Shinarump group extends from the Grand Canyon 
district to the Uinta Mountains, and Dutton has named the junction 
of the Grand and Green rivers as a locality where the whole group is 
present in typical development (9, p. 144) and where the conglomerate 
bed exhibits the same characters as in the Shinarump Cliff of southern 
Utah (10, p. 208). Both assertions seem to have been based on 
insufficient knowledge of the section below the Vermilion Cliff sand- 
stone, for no descriptive data appear in the reports of these geologists 
to substantiate the claim. As far as I can ascertain, no geologist 
except Powell has examined the section near the confluence of the 
Grand and Green Rivers and he gives in his reports only general 
statements concerning the strata between the Vermilion Cliff sand- 
stone and the Carboniferous beds referred to the Aubrey. 
In the vicinity of the Henry Mountains Gilbert reports (14) a 
stratum correlated by him with the Shinarump conglomerate at 350 
feet below the Vermilion Cliff sandstone, and some miles southeast of 
the Henry Mountains at Clay Hill divide, H. S. Gane found (7) 
