FAUNA. OF YAHOO CANTOM. 83 



Productus hirsutiforme and Coholm Icevix. Plant remains occur here sim- 

 ilar to those found east of Sugar Loaf, but still less perfectly preserved. 

 The identification of the flora from the former locality places the age of 

 these beds without doubt at the top of the Devonian, in accordance with 

 their stratigraphical position. The corresponding horizon at White Pine 

 Mountain presents still stronger evidence of the Devonian age of the 

 shale; but here, as well as at Eureka, little has been accomplished by 

 investigating this ancient flora. 



Passing to the Pinon Range and the Mahogany Hills in the northwest 

 corner of the district, the Upper Devonian limestone is well exposed in 

 massive beds lying beneath the Diamond Peak quartzite. It is easily deter- 

 mined by its lithological habit and fauna, as well as by its geological 

 position beneath the Carboniferous quartzite. Fossils are known in a num- 

 ber of places, but the localities which have furnished the largest and most 

 varied fauna and offer the most promising return are found on the east side 

 of Yahoo Canyon and north side of The Gate. Near the entrance to 

 Yahoo Canyon the beds have yielded a rich fauna characterized by silici- 

 fied corals. The grouping here is as follows: 



Strornatopora. Pachyphyllum woodmuui. 



Alveolites rockfordeiisis. Spirifera glabra, var. nevadensis. 



Cladopora pulchra. Spirifera disjnncta. 



Syringopora hisingeri. Atrypa recticulans. 



Syringopora perelegaus. Bhynchonella c.astanea. 



Cyathophyllura corniculuni.f Styliola fissurella. 



On the north side of The Gate, at a little higher horizon and directly 

 beneath the quartzite, there is exposed a fine section, 500 feet in thickno-. 

 of massive blue limestone, passing into shaly beds, in places almost fissile. 

 Fossils characteristic of the Upper Devonian are abundant throughout the 

 beds. The limestone yielded the following species: 



Stromatopora. Orthis tulliensis. 



Syringopora hisiugeri. Productus lachrymosa, var. liina. 



Syringopora perelegans. Productus schninardiauus. 



Cyathophyllum corniculum. Productus speciosus. 



Disciua iniuuta. Productus stiginatus. 



Orthis impressa, Productus subaculeatus. 



