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80 TRANSACTIONS OF THE 
Where the ozokerite occurs the strata are intersected 
by fissures, zones of brecciation and parallel jointing. 
Those fissures and spaces between the brecciation contain 
the ozokerite, usually as thin sheets but sometimes as dike 
—like bodies several inches thick. The fissures are nearly 
vertical and strike from N. 10 degrees W. to N. 60 de- 
grees W. The thickness of the deposit is variable both 
laterally and vertically. 
In the past rock asphalt has been called bituminous 
sandstone, but the name rock asphalt is gradually being 
adopted, especially in Utah. The largest deposits in the 
state lie south and east of Vernal, north of the White River 
and between Ashley and Uintah Valleys®. This deposit 
attains a thickness in places of twenty feet but at present 
is too far from a railroad for successful commercial ex- 
ploitation. Another deposit occurs south-east of Thistle 
in Spanish Fork Canyon, and still other immense deposits 
are found (a) in the tributaries of Whitmore Canyon, near 
Sunnyside, having a bituminous content of from 10 to 12 
per cent, rather evenly distributed; (b) at the head of 
Willow Creek, a tributary of the Green River in the Book 
Cliffs Mountains; (c) in the Laramie sandstones near 
Jensen on the Green River. 
A deposit of bituminous limestone occurs at the head 
of the right hand fork of Tie Fork, a canyon entering 
Spanish Fork Canyon two miles west of Clear Creek Sta- 
tion. This deposit occurs in horizontal veins of from two 
to four feet in thickness and carries 12 to 20 per cent of 
asphalt. 
An area underlaid by bituminous limestone about 50 
miles long east and west, by 10 miles wide north and 
south, lies just north of Colton and south of Strawberry 
Creek from Antelope Creek on the east to near Thistle on 
the west®. 
In reviewing the literature of the work done on these 
products, one finds that considerable has been published 
concerning gilsonite and ozokerite but not much about 
wurtzellite, tabbyite, and rock asphalt. Day’ attempted to 
5H & MJ. Vol: 17,'\p.. 115. 
®U. S. G. S. 17th Annual Report, p. 332. 
TJournal of Franklin Institute, Sept. 1895. 
