THE VALLEY CITY GRABEN, UTAH* 
C. L. DAKE 
Rolla, Missouri 
During the course of reconnaissance work undertaken in 1917 
over much of southern Utah, the writer observed an interesting 
structure which seems worthy of a brief description. It is located 
in Townships 22 and 23 South, Ranges 19 and 20 East, in Grand 
County, and is plainly visible along the road between Thompsons 
and Moab, near Valley City. 
STRATIGRAPHY 
The stratigraphy of the general region is simple, and is well 
described in reports by Lupton? and Woodruff, to which the 
reader is referred for greater detail. The oldest formation exposed 
in the immediate vicinity is the Dolores, consisting of about 1,300 
feet of variegated sandy shales and soft sandstones of Triassic age. 
Red, pink, and gray are the dominating colors. The formation is 
relatively nonresistant, and usually comprises plains and broad val- 
leys. Above the Dolores occurs the La Plata sandstone, probably 
Jurassic in age. This is the most prominent formation in the dis- 
trict, and consists of two tan-colored, massive, highly cross-bedded 
sandstones separated by about 100 feet of red sandy shale. The 
sandstones are prominent cliff-makers and form the pronounced 
fault-line scarp near Court House Spring on the Thompsons- 
Moab road. Occasional lenses of unfossiliferous limestone a few 
feet thick and a few yards in extent were noted in the sandstone 
in places. Above the La Plata sandstone occurs the McElmo 
formation, of Jurassic age, consisting of about 1,000 to 1,200 feet 
« Published by permission of Valerius, McNutt, and Hughes, Consulting Petroleum 
Geologists, Tulsa, Oklahoma. 
2 C. T. Lupton, “Oil and Gas near Green River, Grand County, Utah,” U.S. Geol. 
Survey, Bull. 541 (1914), p. ITS. 
3E. G. Woodruff, ‘Geology of the San Juan Oil Field, Utah,” U.S. Geol. Survey, 
Bull. 471 (1912), p. 76. 
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