252 W. N. LOGAN 
THE SOUTHERN UINTA AREA 
Ashley Creck."—The thickness of the Jurassic beds on Ashley 
Creek is estimated to be about 750 feet. Of this thickness 50 feet 
are blue and drab colored shales and limestones carrying Gryphea 
calceola, Pseudomonotis (Eumicrotis) curta and Belemnites densus. 
This stratum corresponds to the more densely fossiliferous zone 
of other localities. As the vertical range of the fossils is not 
given it is difficult to say whether all of the 750 feet should be 
included in the Jura. 
Near Peoria on the western end of the range a basal lime- 
stone contains Pseuwdomonotis curta and is followed by a group of 
shales and marls. No thicknesses are given for this area. 
Wasatch Range.2—In Weber canyon of the Wasatch Range the 
Jurassic is estimated to have a total thickness of 1600 feet. The 
lower part which consists of yellow and bluish limestones and 
calcareous shales has a thickness of 600 feet. It contains the 
following fossils: Cucullaea haguet;, Pleuromya subcompressa, 
Myophoria lineata; Myophoria sp. and Volsella scalpra. As the 
upper 1000 feet of arenaceous texture is unfossiliferous it is 
more than probable that it is not of Jurassic age. As the ver- 
tical range of the fossils is not given we have no means of ascer- 
taining how much of the 600 feet may, also, belong to another 
period. 
At the mouth of Thistle Creek in Spanish Fork Canyon the 
following fossils were found: Lyosoma powelli, Camptonectes 
stygius and Pinna sp. 
THE SOUTHERN UTAH AREA 
According to Dutton3 the known Jura of Southern Utah hasa 
thickness of from 200 to 400 feet. The formation consists of a 
series of calcareous and gypsiferous shales. The beds are dis- 
tinctly fossiliferous and thin out toward the south, entirely dis- 
appearing in northern New Mexico and Arizona. A few fossils 
have been collected from a number of localities in the region. 
*KinG: Geology of the goth Parallel, Vol. I, p. 292. 
2 KING: l. c. p. 293. 3 Geology of the High Plateaus, Utah, p. 150. 
