CENTRAL AOT) EASTEEK NEVADA. 415 



tain. Here the sandstone and limestone formations have been considerably 

 distorted. At one place both formations are seen dipping westerly. On the 

 summit of Mokomoke Momitain the limestone is found lying almost horizon- 

 tally. Immediately above the argillaceous shale occurs a belt of fine-grained, 

 reddish-yellow sandstone, whose thickness is estimated at about 300 feet. 



Next in order above the sandstone occurs a body of light-yellow, granu- 

 lar limestone. The formation is highly fossiliferous and rich in remains of 

 well-marked carboniferous types. From the sandstone to the summit of the 

 ridge we have several hundred feet of the limestone exposed, but, as nowhere 

 within the district do the overlying beds appear, the entire thickness cannot 

 be given. 



At Swansea, in Silver Canon, the argillaceous shale, sandstone, and car- 

 boniferous limestone are found. The beds are very much disturbed, and 

 occupy only a limited area. 



The paleontological evidence of the position of the White Pine rocks is such 

 as to determine conclusively the age of both the upper and lower limestone for- 

 mations. The clue to the age of the other beds, judging from the fossils alone, 

 is not quite as satisfactory. Their position, however, between well-defined 

 Devonian and Carboniferous rocks is sufficient proof that they belong either to 

 the one or the other of these periods. In the Devonian limestone, as far as 

 known to the writer, no fossils have as yet been obtained from the lower beds. 

 The overlying beds, however, are in many places highly fossiliferous, and for 

 several hundred feet below the uppermost stratuni, fossils of well-marked 

 Devonian types are abundant. 



The writer is indebted to Mr. J. E. Clayton, a mining engineer residing at 

 Hamilton, for information in regard to the localities of many interesting fos- 

 sil-bearing beds, and also for many valuable specimens from his private col- 

 lection. 



The most interesting fossiliferous beds may be found upon the summit of 

 Treasure Hill, along the east bluff, in the neighborhood of the Argyle mine; 

 on the east side of the Blue Ridge, above Hamilton, and near the summit of 

 Babylon Hill. Upon Treasure Hill may be found Diphyphijllum, Chonophyilum, 

 y Fafosites, Alveolites, Matrocheilus, Orthoceras, Acej^mmd^ Atrypa reticularis, 

 Spirifer engelmanni, Spirifer utahensis. In addition to many of the above. 



