284- Mr. 'RohhexdiS on the former Level of the German Ocean, 



vian" origin of the marine deposits in the Norfolk valleys. 

 I will not ask whether these amount to a positive and irrefu- 

 table demonstration of the fact— it would be too much to re- 

 quire, — but do they afford any admissible even presumptive 

 evidence in support of the peremptory conclusion that has 

 been drawn? They have utterly failed in their attempts to 

 establish a continuity of position and identity of character 

 between these beds and any antecedent formation ; and unless 

 these two points can be clearly substantiated, all the rest is 

 mere fable and conjectui'e. 



On the other hand, let them observe the connection and 

 harmony of the following train of inferences, deduced from 

 the general phaenomena of this district. 



1 . The masses of sand and gravel, here universally cover- 

 ing the chalk, denote by their elevation that the waters which 

 formed them were raised between 300 and 400 feet above the 

 range which the ocean now takes. 



2. In the last stage of the retreat of these waters to their 



{)resent level, they must have been drawn off through the val- 

 eys which open to the sea; and consequently there must have 

 been a period, during which their streams entirely filled, and 

 were confined to, these channels. 



3. These valleys contain extensive beds of marine shells, 

 which are not only spread over the bottom of them, but also 

 at various points rise on each side to the height of about forty 

 feet above the intervening alluvial formation. They terminate 

 on the edge of the valleys, the uppermost of them resting on 

 the surface of the sand, with a thin coat of vegetable earth 

 above them, and consisting almost exclusively of the recent 

 species which now inhabit the shores of the German Ocean. 



4. At the earliest dawn of history upon this region, its val- 

 leys formed a connected aestuary ; we have positive evidence, 

 that at the close of the eleventh century the salt tides still 

 covered a considerable portion of them, and from that time 

 they have been gradually converted into pasture land. 



In this series, the place of the marine remains (at least of the 

 highest of them) is so distinctly pointed out and clearly deter- 

 mined, that it seems almost impossible to entertain a doubt upon 

 the subject. They must have been deposited after the banks 

 of gravel and sand were completed ; for they rest upon them. 



They must have been formed at that period, when the 

 waters occupied only the troughs of the valleys ; for they are 

 confined within the same limits. 



They must have been left by the retreat of those waters to 

 their present level; for they are the latest relics of the sea: and 



They 



