402 C. L. Heese — Influence of Swamp Waters in 



ters of his Appomattox with the idea of oceanic submergence, 

 unless under conditions for which, in the actual state of our 

 knowledge or conjecture regarding the climatic and surface 

 conditions of the pre glacial epoch, we have there no adequate 

 explanation. I therefore do not venture to suggest any for the 

 Atlantic region, but do suggest for the critical region which 

 has formed the subject of my special studies, such explanation 

 as seems to me warranted by the regional facts, applicable to a 

 very wide stretch of country distinctly correlated with the 

 great axis of the Mississippi valley. The one prominent and 

 indisputable fact, that after the Vicksburg period there has 

 been a steady increase of fresh-water (or decrease of marine) 

 conditions within the Gulf region, does not, so far as I am 

 aware, apply to the Atlantic coast ; and this distinctive and 

 important feature requires special consideration and explana- 

 tion. The latter may be found in the glacial phenomena, or 

 as McGee has suggested to me, in the discharge of the great 

 lakes of the continental interior toward the Mississippi valley, 

 or in both combined.. In either case these conditions have no 

 analogue on the Atlantic slope south of the Hudson at least ; 

 and it would be precarious to attempt to gauge the two regions 

 according to the same preconceived ideas. No one recognizes 

 more than I do, the relative scantiness of our present informa- 

 tion in the premises, particularly in view of the wide extent of 

 country involved in any and every change in or near that com- 

 mon reference plane, the Gulf of Mexico. I feel confident 

 that the practical recognition of the fundamental importance 

 of this plane for the interpretation of the interior continental 

 movements, and the consequent active investigation of its 

 borderlands as starting points, will quickly lead to the solution 

 of many problems that have heretofore puzzled geological in- 

 vestigators at the heads of its drainage system. 



Art. XLIX. — On the Influence of Swamp Waters in the 

 Formation of the Phosphate Nodules of South Carolina / 

 by Chas. L. Keese, Ph.D. 



Ix the introduction to Bulletin, . E"o. 46, of the IT. S. Geo- 

 logical Survey on " The JSTature and Origin of Deposits of 

 Phosphate of Lime," by P. A. F. Penrose, Jr., Prof. Skaler 

 suggests that the South Carolina phosphates may have been 

 formed by the action of swamp waters lying on beds of marl, 

 and it was with this idea in view that I determined to look 

 into the chemistry of. the subject. 



