116 TRANSACTIONS OF THE [jAN. 18, 



Atlantic basin, " counterparts of the three great movements of 

 tlie North American continent, which have characterized in 

 American geology the epochs of the Quaternary age."* 



Professor Heilprin's conclusions are : 



1. The present form of the Bermudas bears no relation to the 

 ring of an atoll, except in so far as the outer boundar}' may be 

 more or less coincident with the boundaries of an ancient atoll. 

 2. The existence of an atoll in the present position of the Ber- 

 mudas is not demonstrable. 3. The height of land in the archi- 

 pelago was formed during a period of elevation, when seemingly 

 the entire archipelago was a connected or continuous piece of 

 land, extending as an oval island to what is now the bounding 

 reef on the north and south. It is impossible to determine the 

 absolute amount of elevation above the water, but it appears to 

 have been not less than seventy or eighty feet and it may have 

 been considerably more. 4. The lagoons and sounds were formed 

 during a*period of subsidence which followed upon that of eleva- 

 tion and is seemingly still in progress or was so until a compara- 

 tively recent period. The great degradation of the coast line 

 took place at this time. It is impossible to determine the 

 amount of such subsidence, but it was at least sixty or seventy 

 feet and not improbably much more.f 



Professor Heilprin argues energetically against the proposition 

 that the sounds and harbors owe their origin to solution of rock 

 supports and shows that instead of losing material by solution 

 they are gaining constantly by deposits. He combats with 

 equal energy the idea presented by Rein that the basins are due 

 to '' normal erosion assisted by the breakages which in one form 

 or other ai-e likely to follow the honeycombing of the rock."| 

 He discusses the coral reef problem elaborately and defends the 

 subsidence theory with decided emphasis, while he is careful to 

 state that in using the term " subsidence " he uses it " in a rela- 

 tive sense indicating a depression or submergence of the land 

 beneath the sea" without asserting "whether the submergence 

 was due to a positive movement on the part of the land, or to a 

 change in level (rise) in the water." § 



Professor A. Agassiz's study was more in detail than that of any 

 predecessor since Rice, and liis discussions cover much ground 

 untouched by any others. He regards the Bermudian rocks as 

 seolian throughout, the limestone and sandstone as a continuous 

 deposit, and cannot accept any identification of the fossiliferous 

 rock of St. George, Hamilton harbor and elsewhere as beach 



*Loc. cit., p. 18. 

 tThe Bermudas, p. 46. 

 JLoc. cit., p. 44. 

 gLoc. cit., p. 77. 



