FAUNA OF THE POGONIP. 53 



A similar grouping of fossils was procured in the Fish Creek Moun- 

 tains a short distance below the quartzite, numerous localities yielding 

 nearly identical lists: 



Receptacotites ellipticus. Modiolopsis occidens. 



Receptaculites elongatus. Modiolopsis pogouipeiisis. 



Beceptacnlites mammillaris. Pleurotomaria sp? 



Cystidean plates. Maclurea sp ? 



Ptilodictya- sp? Orthoceras multicameratum. 



Monticulopora sp ? Endoceras protciforme. 



Ortliis perveta. Aini)hioii nevadensis. 



Tellinouiya contracta. Ceraurus sp? 



On the north slope of Surprise Peak, just below the quartzite, the lime- 

 stone supplied the following : 



Receptaculites mainmillaris. Rapliistoma nasoui. 



Cystidean plates. Pleurotomaria ? 



Ortliis perveta. Maclurea annulata. 



Ortliis tricenaria. Leperditia bivia. 



A convenient locality to those visiting Eureka and wishing to exam- 

 ine the Upper Pogonip beds may be found on the west side of Caribou 

 Hill, which has furnished a few typical forms : 



Ortliis perveta. Receptaculites maminillaris. 



Ortliis tricenaria. Maclurea auimlata. 



Asaphus cariboueusis. 



Other localities which have presented evidences of the same horizon 

 may be found in Goodwin Canyon, at the head of Lamoureux Canyon, 

 and in the limestones not far from the line of the general section E F, 

 atlas sheet xm. 



This grouping of fossils from the summit of the Pogonip limestone is 

 of special interest on account of the commingling of species and the position 

 of the strata. Ascending in the beds it will be found that the Cambrian 

 fauna entirely disappears, the life of the Middle Pogonip gradually 

 passes away, and new species come in until the grouping of the fauna 

 presents an aspect peculiarly its own. Two species of the genus Modiolop- 

 sis, and the characteristic fossil, Tettinomya contracta, foreshadow still higher 

 strata, indicating the coming in of the Trenton horizon. The summit of 

 the Pogonip is also marked by an increase in the number of species of 



