INTERPRETATION OF THE SECTIONS 495 



characteristic of or at least found in torrential deposits formed entirely 

 on dry land. Indeed, it is quite apparent that a number of the most 

 marked characters of the formation are difficult, if not impossible, of ex- 

 planation on any other theory of origin. Why, then, do we find in the 

 literature the common reference of this conglomerate to an "estuarine" 

 or a "lagoon" or a "seashore" deposit ? This is in part no doubt due to 

 the general disinclination to take another of the formations formerly 

 unquestionably regarded as marine out of this category and add it to the 

 growing list of formations now regarded as of continental origin. Some 

 geologists, and apparently not a few, view every such attempt with jealous 

 distrust, and they hold out to the very last for the old accepted, but never 

 proved interpretation long after all the signs in the case point to the 

 necessity of accepting the new. But there are two other reasons in the 

 present case why the marine origin of the Shawangunk conglomerate is 

 held to by so many geologists. The first is that it precedes and is inti- 

 mately associated with the deposits of salt and gypsum which charac- 

 terize the Salina group of the interior, and which many geologists are 

 still loath to interpret in any other than the orthodox way prescribed by 

 Ochsenius. 91 The second reason is the recent discovery of Eurypterid 

 remains in the black shales intercalated between the conglomerate layers. 

 Now, Eurypterids have almost always been regarded as marine animals, 

 especially during the earlier periods of their reign on the earth, in spite 

 of the suggestive discussion by Professor Chamberlin, in which it was 

 shown that Eurypterids were more likely inhabitants of fresh water and 

 took to a marine habitat later. It was not that fresh-water Eurypterids 

 were unknown, for beautifully preserved specimens had repeatedly been 

 obtained from terrestrial deposits in close association with coal plants. 

 But it was and is believed by many that the deposit which most satis- 

 factorily preserves these organisms, the Bertie water-lime, must be 

 marine, and therefore the Eurypterids must be marine, and therefore all 

 Siluric Eurypterids must be marine, even though they become fresh- 

 water forms in the Devonic, and therefore, finally, all deposits containing 

 Eurypterids before the Devonic must be marine. 



We may now proceed to look more carefully into these questions and 

 see if the Salina deposits really were marine and if the Eurypterids of the 

 Siluric were necessarily so. If we can establish that in neither ease is 

 the marine hypothesis the best one explaining these deposits or account- 



91 See, for example, the recent elaborate discussion of the origin of the Salina salts by 

 Clarke and Ruedemann in the Eurypterid memoir, which does not cvcii mention the 

 desert theory. 



