OF ARTS AND SCIENCES. 235 



nensis. If the beds are classed after the principal genus found in 

 them, as has been done in Scandinavia, where the divisions or groups 

 are called " zone of Paradoxides," " zone of OlenelU" " zone of Asa- 

 phus,'' &c., there are at Eureka two well-marked zones, — the " zone 

 of OlenelU " at the base of the " Prospect limestone," and the " zone 

 of Dihelocephali, reaching even the " Eureka quartzite." The genus 

 Dikelocephalvs is one of the most constant and the most universal in 

 the Supra-Primordial of North America. 



Thus it will be seen that the " Taconic System " is perfectly devel- 

 oped, as well at the Grand Caiion as at Eureka ; and that all the 

 horizons, or palasontologic zones, have been found there of the typi- 

 cal Atlantic regions of the Taconic in America, as I have shown 

 them in the general and theoretic section. One alone has not been 

 recoginzed, — the " zone with Paradoxides " of Braintree, St. Mary's 

 Bay, and St. John, New Brunswick. But the Infra- Primordial is 

 well represented in the " Chuar group " of the Grand Canon ; the 

 Primordial, in the zone with OlenelU at Eureka, Pioche, and Oquirrh ; 

 and the Supra-Primordial in the zone with DUcelocephall. 



These divisions terminate, as at Lake Champlain and Saratoga, with 

 a covering in discordant stratification of a mass of sandstone identical 

 with the " Red Sandrock " or " Potsdam sandstone," which Mr. Wal- 

 cott calls " Tonto Group " and " Eureka quartzite." 



The classification here given only differs in the groupings and 

 denomination of the systems. I will give my reasons later for not 

 using the terms " Cambrian " and " Silurian " as they are used by 

 Messrs. Walcott and Hague ; but the divergence of opinion on the 

 general classification and the use of names does not at all diminish the 

 value of the remarkable observations in the resrion of the Great Basin 

 and the Grand Canon made by these savants. Their researches and 

 discoveries are of great importance, and their value cannot be too 

 highly appreciated. 



V. Geographtcal Distribution of the Taconic. — Norway. 



It is not necessary to review all the localities and regions of Amer- 

 ica wheie the Taconic System and the Primordial fauna have been 

 discovered ; it is sufficient to say that America has far more than the 

 Old World of depositions already described, and of variety in the 

 fossils collected ; and it appears from what we know, that life was 

 manifested in the New World under forms which have preceded the 

 apparition of similar ones in Europe. We may say with confidence 

 that from Newfoundland and Belle Isle to Eureka and the Grand 



