100 Prof. Rogers's Address, 6fc. 



In a case of this kind a nomenclature on the plan here proposed, will 

 be found to obviate all confusion. When speaking of the strata, as they 

 exist in New York, we would call the Trenton limestone and Utica slate, 

 for example, Matinal newer limestone, and Matinal older slate, but 

 when these become blended, as in Virginia, the portion of the series 

 which they occupy, the Matinal argillaceous limestone group, or Mati- 

 nal middle group, while the strata on the same general horizon in East 

 Tennessee, would be called the Matinal encrinal limestone, or Matinal 

 coral marble, as the case might be, appending when necessary to each 

 such name, that of the district in which the rock or group attains its 

 fullest development. In those instances where any thing short of a mi- 

 nute analysis of local application, is impracticable, as is the case perhaps 

 of the Cincinnati blue limestone, the general term Matinal series will be 

 most appropriate. If that mass should in any district acquire a binary 

 or ternary subdivision, the respective parts may be called the Matinal 

 older limestone, &c., of Ohio, a mode of naming which is amply de- 

 scriptive as to each requisite of time or plan in the series, of composi- 

 tion and locality, and which furthermore takes nothing for granted. 



Before leaving this important but difficult subject of classification and 

 nomenclature, permit me very briefly to indicate why I conceive that the 

 prevailing method of naming rocks without regard to their relationships 

 of age, but solely by titles drawn from the spots or districts where they 

 occur, must seriously retard our science. If the names be derived from 

 a single district, even an extensive one like New York, however rich in 

 strata and however ably these should be explored, only a portion of the 

 names, generally a small part of them, will really be assigned to forma- 

 tions which are there fully or typically developed, for we well know, that 

 no single corner of a vast basin can ever contain but a few of its deposits 

 in a condition of maximum expansion, and richness in organic remains. 



If geographical terms are to be employed it would be more appropri- 

 ate to select those belonging to districts any where in the basin where 

 the formations are found to be most amply represented. On this plan 

 the names would be found to possess a wider significance, than when 

 all are chosen from one region, yet as geographical names, they would 

 lack suggestiveness when applied to any one local district. If on the 

 other hand, the rocks are to receive different local titles in the different 

 territories explored, then will our descriptive geology be rendered almost 

 unintelligible, by a crowd of synonyms, and every attempt at extensive 

 comparison, every effort to read in this ample page of nature's great 

 history, some of her higher laws, will be made doubly arduous. 

 To he concluded in our next No. 



