Denudation of the Lake District. 473 



would commence with these movements, but was probably com- 

 pleted only as the whole tract of country emerged slowly from be- 

 neath the surface of the sea. If we reject the glacial theory in its 

 application to the transport of blocks, as totally inadmissible in the 

 case before us, this emergence must necessarily have taken place 

 subsequently to the transport of blocks from the Cumbrian moun- 

 tains across Stainmoor. 



The author conceives the valleys of the district to have been 

 formed during this gradual emergence ; the action of denuding 

 causes being facilitated by previous dislocations, the masses, the 

 removal of which formed the valleys, would at the same time be 

 transported and spread over the surrounding country. The forma- 

 tion of the existing lakes must have been one of the most recent 

 events in the geological history of this region. 



Period of Transport of Erratic Blocks.— The author thinks that 

 geologists have frequently limited too much the period during 

 which the transport of blocks may have taken place. When blocks 

 are found reposing on an undisturbed formation, the only con- 

 clusive inference which can be drawn from the fact is, that the last 

 stage of their movement was posterior to the deposition of the beds 

 on which they rest. If the beds be much disturbed, but all the 

 irregularities and asperities of its external surfaces worn away by 

 long-continued attrition, we may generally conclude that the same 

 action would have worn away any blocks previously existing on 

 its surface, and therefore any blocks now existing on such surface 

 must have been lodged there subsequently to its denudation. Also, 

 when diluvial gravel contains organic remains, we may conclude 

 that the last stage of its movement must have been subsequent to 

 the existence of the animals whose remains are entombed in it. To 

 contend, for instance, that the diluvial gravel of Norfolk was not re- 

 moved from its original site till the post-tertiary period, is to draw 

 an inference which the author deems altogether inadmissible. 



The great mass of diluvium from the Cumbrian mountains re- 

 poses on nothing more recent than the new red sandstone, and the 

 author conceives that its transport might begin with the elevatory 

 movements which disturbed that formation, when the surface of the 

 present mountainous district began to rise permanently above the 

 surface of the ocean, and the valleys began to be formed. This is 

 the more remote limit of the period to which the transport of 

 diluvium and blocks can be referred ; the other limit is the emer- 

 gence of Stainmoor (over which so many blocks passed) from be- 

 neath the surface of the ocean, assuming the total inadequacy of 

 the glacial theory to account for that transport. The present 

 height of Stainmoor is stated to be about 1500 feet above the sea; 

 consequently an elevation of from 1500 to 2000 feet must have 

 taken place in these regions since the transport of the Cumbrian 

 blocks across the Penim ridge — a fact which appears corroborative 

 of the author's opinion, that the district had scarcely emerged from 

 the ocean at the more remote of the above-mentioned limits of the 

 possible period of transport. 



