PALEOZOIC EOCKS. , 365 



Mr. J. E. Clayton found, in a belt of dark limestone, a number of fossils, 

 among which the following have been determined by Messrs. Hall and 



Whitfield : 



Spirifer alha-pinensis. 



Spirifer centronatus. 

 Atliyris planosulcahis. 

 Atliyris Claytoni. 

 Euomplialus UtaJiensis. 

 Terehratula TJtaliensis. 

 Cryptonella f 



These have the same general aspect, and are many of them identical 

 forms with those found in Ogden and Logan Canons in this range and in 

 Dry Caiion in the Oquirrh Mountains, and may be considered to indicate 

 the Waverly horizon. 



A peculiar belt of white calcareous quartzite in the limestones on the 

 summit of the ridge above the Flagstaff Mine, full of indistinct casts of 

 fossils, among which a long cylindrical cavity, regularly ribbed in circles, 

 parallel to the base of the cylinder, about one-eighth of an inch apart, is the 

 most frequent, with also the interior mould of a Spirifer resembling S. canie- 

 rafus, recalls a similar quartzite at White Pine, Nevada, occurring below 

 the black shales which mark the dividing line between the Carboniferous 

 and Devonian. 



The Wahsatch limestone body can be traced by its white cliffs eastward 

 to the ridge overlooking the head of Big Cottonwood, where it is more 

 coarsely and distinctly crystalline, and its beds bent into Z-shaped folds, and 

 traversed by dikes of syenite-porphyry about 20 feet wide. Of these, no 

 less than three can be seen on one spur, the strata being abruptly curved 

 at the contact-line, showing they have followed lines of weakness and 

 fracture. One variety resembles that already described from Big Cotton- 

 wood, being very rich in hornblende and titanite, with mostly plagioclase 

 feldspar, and but little mica. Another externally is more like the diorite 

 from the American Fork divide, showing neither orthoclase, mica, nor 

 titanite to the unaided eye. 



The upper tributary canons of Big Cottonwood run more or less in 



