42 IRON ORES OF IRON SPRINGS DISTRICT, UTAH. 
CHARACTER. 
The Claron formation is mainly limestone with numerous thin 
layers of conglomerate and a few heavy beds of sandstone. It is 
separated from the Cretaceous sandstones by a basal conglomerate 
2 to 25 feet thick, made up of coarse quartzite pebbles where it is 
thick and of finer pebbles where it is thin. Below it is generally a 
soft, pink, calcareous sandstone or soft limestone, which probably 
represents residual material from the weathering of the Pinto forma- 
tion formed before the deposition of the Eocene. It is only a few 
feet thick and under it are the red and yellow sandstones of the 
Cretaceous. Locally the underlying Cretaceous bed is a coarse con- 
glomerate difficult to distinguish from the basal conglomerate of the 
Claron formation. In most places it was eroded away before the 
deposition of the Claron. Above the basal conglomerate is another 
conglomerate, thin and sandy, with small pebbles, and discontin- 
uous. It is like numerous other conglomerates interbedded with 
the limestone higher up in the formation. These as a rule are thin 
and any single bed is not continuous over a large area. The pebbles 
are small and are separated by a matrix of coarse sandstone. They 
are mainly quartzite, limestone, quartz, and chert, in varying pro- 
portions in the different beds. The conglomerate beds may grade 
laterally into coarse sandstone beds. 
The principal part of the formation is a sandy limestone varying 
from white and gray to pink, red, and purple. On weathering, the 
sand grains, being less easily dissolved, protrude above the surface and 
give it a rough pitted appearance. Some of the layers have spherical 
and irregular cherty concretions which vary from less than half an 
inch to an inch or more in diameter. The limestones are more resis- 
tant to erosion than the sandstones and conglomerates of the Eocene 
and Cretaceous, and hence form cliffs and ridges above them. On 
weathering they acquire bright-red colors, making the exposures con- 
spicuous for many miles. 
Heavy yellowish-brown sandstone beds containing a number of 
discontinuous layers of conglomerate are interbedded with the 
limestones. Owing to faulting, it is hard to tell the thickness of 
these sandstones, but it may be several hundred feet. In some places 
they are distinguished with difficulty from the Cretaceous sandstone. 
Criteria for their identification are their occurrence in the midst of 
Tertiary rocks, and the absence of a basal conglomerate between 
them and the overlying limestone and conglomerate beds. The 
first of these might be caused by faulting, but the invariable absence 
of the basal conglomerate in such cases was taken as evidence that 
they were Tertiary. 
