184 



great confusion as to the nomenclature of the superpo- 

 sition of strata. He had felt the necessity of introducing 

 some new terms, and he proposed the following, viz : — 



1. Conformable Continuous. 



2. Conformable Intei'rupted. 



3. Unconformable Continuous. 



4. Unconformable Interrupted. 



He illustrated the application of the terms by the aid of a dia- 

 gram, representing three strata — Limestone below, Shale interme- 

 diate, and Sandstone the uppermost, designating them by A, B, and 

 C respectively. If we find a partial blending of organic remains, 

 and partial intermingling of materials, with evidence of continuity 

 in time of deposition, this condition may be expressed by the 

 first term. If the strata A and C are together in superposition, 

 without physical sign of bi'eak, and yet with abrupt omission in 

 types of life, it should be designated in the second category. If 

 the sequence of the strata is uninterrupted, and yet a displace- 

 ment exists from some physical disturbance, the third term is 

 applicable. The fourth term would designate C, unconformably 

 upon A, and at the same time an exclusion of B. 



The recognition of such distinctive terms would much tend to 

 promote the science of Geology. 



Dr. Jackson observed, that amongst other examples of 

 the interrupted series, there is a fine illustration in the 

 superposition of the Sandstones of the Connecticut 

 River, upon the Gneiss, Granites, and Mica-Slate of 

 New Hampshire, at Northfield, Mass.; where the whole 

 PalsEOzoic Series is wanting. 



Dr. Jackson expressed himself in favor of the nomen- 

 clature of Prof. Rogers, because it was both explicit and 

 succinct. 



The Chairman announced the death of Prof. Michael 

 Tuomey, of Alabama, one of the Corresponding Mem- 

 bers of the Society, and requested Prof. W. B. Rogers 

 to propose a resolution suitable to the occasion. 



