ALPHA AND FUSILINA PEAKS. 159 



fossils, the best locality noticed being on the summit of the ridge about 

 one-third of a mile south of the peak and 150 feet below the highest point. 

 Ten species were obtained here, the list being given on page 91. The two 

 most interesting species are Spirifera trigonalis and Camarophoria cooperensis, 

 the latter identical with the Missouri form. Both of them, as pointed out 

 by Mr. Walcott, are characteristic of the lower Carboniferous in the Mis- 

 sissippi Valley. It is these two species that serve to correlate the low lime- 

 stone ridges south of Newark Mountain with the base of the Lower Coal- 

 measures. 



Immediately northwest of the crest of the ridge the strata dip easterly, 

 and at about the same distance below the summit, as observed on the 

 opposite side of the peak, the quartzites come in conformably beneath the 

 limestones, dipping easterly into the ridge. No considerable thicknesses of 

 quartzites are exposed, as they are abruptly cut off by the profound Alpha 

 Peak fault, which brings the Upper Coal-measure limestones unconform- 

 ably against them. Following the quartzites southward, they are seen to 

 be much broken up and dislocated, and southwest of the peak again dip 

 westerly, with an angle of about 15, a dip which they maintain as far 

 south as Bold Bluff, where they terminate abruptly against the Newark 

 fault. By reference to atlas sheet vi the position of the quartzites may be 

 readily made out, completely encircling Diamond Peak on all sides. 



Newark Fauit.-This line of faulting, starting in at Bold Bluff, trends 

 southward along the abrupt west wall of Hayes Canyon, following the 

 contact between the two dissimilar formations the gray Lower Coal- 

 measures and the black White Pine shale. It is easily traceable for nearly 

 3 miles. At the southern end it gradually trends off to the southeast, com- 

 pletely cutting off the shales, as well as the Diamond Peak quartzite, and 

 at the mouth of Hayes Canyon brings the Lower Coal-measures directly 

 against the Nevada limestone of Newark Mountain. 



Region of Alpha and Fusiiina Peaks. The Lower Coal-measure limestone 

 overlying the Diamond Peak quartzite forms an unbroken narrow ridge, 

 extending southward for over 9 miles, and falling away gradually until 

 it passes beneath the Quaternary of the valley. This ridge presents great 

 simplicity of structure and monotony of appearance, the beds exhibit- 



