246 THE CAMBRIAN. Ibull.81. 



HAMBURG. 



The Hamburg limestone and the Hamburg shale are names used by 

 Mr. Arnold Hague, in 1881, to designate the Upper Cambrian limestone 

 and shale of the Cambrian sect ion of the Eureka district, Nevada. The 

 limestone is superjacent to the Secret Canon shale and subjacent to 

 the Hamburg shale. The latter is characterized by a well developed 

 Upper Cambrian fauna. 1 



SECRET CANON. 



This name was applied by Mr. Arnold Hague, in 1881, to a band of 

 shale in the Cambrian section of the Eureka district, superjacent to the 

 Prospect Mountain limestone and subjacent to the Hamburg limestone, 

 characterized by a fauna that may be referred to the upper portion of 

 the Middle Cambrian. 2 



KATEMCY. 



Prof. Theodore B. Comstock, in describing the Upper Cambrian rocks 

 of the central area of Texas, proposed the name 4< Katemcy" for the 

 "Potsdam series,' 7 or Upper Cambrian. (?) 3 This terraue is named from 

 the beds exposed in the valley of Katemcy Creek, Mason County. 



RILEY. 



This name was proposed by Prof. Theodore B. Comstock, for a series 

 of sandstones which he considered to be superjacent to the Hickory 

 series of the Central Texas, Cambrian section, and subjacent to the 

 Katemcy or Potsdam series. He referred it provisionally to the Middle 

 Cambrian zone. 4 



HICKORY. 



This name was proposed by Prof. Theodore B. Comstock, for a series 

 of strata that he considered to underlie the typical Potsdam Sandstone 

 of the central Texas section. He referred the series provisionally to 

 the Lower Cambrian. 5 



CONNASATJGA. 



This name was proposed by Mr. C. Willard Hayes, for the Cambrian 

 shales at the summit of the Cambrian section in northwestern Georgia. 

 He correlated it with the Knox shale of Safford's Tennessee section, 

 assigning to it a thickness of l,0i;0 to 2,000 feet. 6 



1 Report (on work in Eureka District). U. S. Geo!. Surv., 2d Ann. Rep., 1880-'81, 1881, p. 27 ; 3d Ann. 

 Rep., 1883, p. 255. 



2 Ibid., pp. 27, 253. 



3 Comstock, T. B. : A preliminary report on the geology of tlie central mineral region of Texaa. 

 First Ann. Rept. Geol. Surv. Texas, 1889, p. 289. 



"Ibid., p. 286. 

 6 Ibid., p. 285. 



6 Tbe ovortbrust faults of tbe soutbern Appalachians. Bull. Geol. Soc. America, vol. 2, Feb. 1891, p. 

 143, pi. 3. 



