W. B. CLARK — TERTIARY OF CAPE FEAE RIVER. 537 



4. That the Council be authorized to prepare a list of exchanges, not to 

 exceed 75 in number. 



5. That the Fellows pay strict attention to the section of the By-Laws 

 providing for commutation of annual dues by a single prepayment of $100. 



The recommendations of the report were adopted by vote of the Society. 



The President then delivered an address on the early history of American 

 geology and geologists, for which the Society, on motion of J. D. Dana, 

 voted its thanks. Professor Dana followed with a few additional statements. 



The first paper of the session was — 



ORIGIN OF THE ROCK PRESSURE OF NATURAL GAS IN THE TRENTON 

 LIMESTONE OF OHIO AND INDIANA. 



BY EDWARD ORTON. 



The paper was discussed by I. C. White, A. C. Lawson, W J McGee, and 

 Professor Orton. It is published in full among the memoirs, pages 87-98. 

 The next paper was — 



ON THE TERTIARY DEPOSITS OF THE CAPE FEAR RIVER REGION. 



BY WILLIAM B. CLARK. 



There is perhaps no portion of our country where the relations of the deposits are 

 less clearly comprehended than in the Coastal Plain bordering the Atlantic. This 

 region varies in width from a few miles in the north to more than one hundred and 

 fifty miles in Georgia, and covers the eastern portions of New Jersey, Delaware, Mary- 

 land, Virginia, the Carolinas, and Georgia, together with all of Florida. Bounded 

 upon the west by the hilly country of the Piedmont Plateau, it stretches away to the 

 coast, an almost level area, except where broken by the meandering rivers and their 

 tributaries, that have as yet but just entered upon their work of denudation. 



To the various formations found represented within this region geologists have 

 applied the taxonomic terms Cretaceous, Eocene, Miocene, etc., although from the 

 meager study of the fossiliferous deposits that has hitherto been made we are by no 

 means certain that these terms can be used with propriety. It is not the intention in 

 this paper, however, to discuss this aspect of the subject, important as it is, for that 

 can best follow a detailed examination of the stratigraphy and paleontology of the 

 entire area. 



The Cape Fear river region presents some of the most puzzling problems in the 

 geology of the Coastal Plain. The formations here represented have been often re- 

 ferred to in geological literature, and quite different opinions held as to their correla- 

 tion. In its topography the Cape Fear river region partakes of the general character 

 of the Coastal Plain, which limits the study of the pre-Quaternary strata mainly to 

 the river banks and accidental excavations. 



There has apparently been little difference of opinion as to the taxonomic position 

 of the greensand marl, that is widely characterized by the accepted Cretaceous fossil 



