64 IRON ORES OF IRON SPRINGS DISTRICT, UTAH. 
So far as known, the Pinto sandstone of the Iron Springs quad- 
rangle bears no fossils, but in the southern part it contains a few 
layers of carbonaceous shales, which were followed southward and 
connected with the anthracite beds of Stoddard Mountain (mapped 
by the Wheeler Survey as Cretaceous and correlated by that survey 
with the Cretaceous rocks on the Colob Plateau), which contain 
numerous workable seams of bituminous coal, associated with oyster 
beds often several feet in thickness. The lower part of the Pinto for- 
mation may be Jurassic, but no evidence for the separation could be 
found. 
The Claron formation contains only a few fossils and these are Car- 
boniferous forms in pebbles in the conglomerates. They are of value 
only in pointing to a Carboniferous limestone outside of the dis- 
trict as the source of the conglomerates. Nevertheless, the Claron 
formation may be satisfactorily correlated with the Tertiary of 
Dutton, a which is the Uinta formation of Smith, 6 on the Markagunt 
Plateau. At the head of Cedar Canyon (Coal Creek valley), cutting 
the Markagunt Plateau, there are 3,000 feet of many-colored Ter- 
tiary limestones, sandstones, and conglomerates. The limestone of 
the Cedar Canyon Tertiary and of the Claron were found to be much 
the same both in regard to general appearance and lithology. Both 
are many colored, although red predominates, and both are sandy. 
The cherty concretions described above are also characteristic of 
many layers in both areas. The Claron formation of the Iron 
Springs district contains more fragmental material in the form of 
beds of conglomerate, but this is to be expected, because it is nearer 
the shore line of the Eocene lake supposed by Smith to lie west of the 
High Plateau region. The Uinta formation is supposed to have been 
deposited in a fresh-water lake basin, which during the early stages 
of deposition extended into southwestern Utah nearly to the Nevada 
and Arizona boundaries but gradually retreated northeastward into 
central Utah. The lower part of the Cedar Canyon Tertiary was not 
seen. It may contain more beds of conglomerate than the middle 
and upper parts, and hence this part might be more specifically cor- 
related with the Claron formation of the Iron Springs district. 
In general, then, the correlation of the Cretaceous and Tertiary 
rocks of the Iron Springs district is based on similarity in lithology, 
thickness, and succession of the Pinto and Claron formations with 
the Cretaceous and Tertiary series, respectively, of the High Pla- 
teaus beginning 15 miles to the east, and on the direct connection 
of the Pinto formation with the Cretaceous coal-bearing beds of 
Stoddard Mountain. The assignment of the underlying Homestake 
formation to the Carboniferous is based on obscure fossil forms and 
a Op. cit. b Smith, J. H., The Eocene of North America: Jour. Geol., vol. 8, 1900, p. 452. 
