58 PLEISTOCEXE DEPOSITS ?sEAR PADSTOW. 



date than B. Supposing D to be a raised beach of subsequent 

 date to B, then the beach (B) would have been raised, the stony 

 loam (C) precipitated upon it, and a subsidence, for which we have 

 no analog}' on any other part of the coast, would have taken place, 

 allowing the deposition of D. 



Apart from the negative evidence of analogy, this hypothesis is 

 untenable ; for, as the old, now consolidated, blown sands bore the 

 same relations to the raised beaches that are exhibited by present 

 blown sands to the modern beaches, the sand would hardly have 

 had time to consolidate before the supposititious subsidence had 

 brought it within reach of the waves, and, if it had consolidated, one 

 would expect to find some trace of a shelf cut in its projecting mass 

 at a height corresponding to the base of the gravel a few yards 

 distant from it. 



The gravel D must be regarded as a fluviatile deposit; but in 

 this case two hypotheses as to its age present themselves. First, 

 let us suppose D to be older than the raised beach. Then the stony 

 loam (C) would first have accumulated, either as an ancient talus 

 or flood gravel, in a channel cut in the slates, at a time when the 

 country stood at a higher level. In process of time, from access to 

 fresh materials (regarding C as fluviatile), or from the selection of 

 this hollow as a line of drainage (regarding C as talus), the boulder 

 gravel (D) would have been deposited, and when the subsidence 

 had progressed sufficiently to allow of the formation of an old beach 

 reef, the previous extension of the fluviatile deposit seaward would 

 have been cut back to the present cliff-line. 



Let us next suppose the gravel D to have been deposited since 

 the raised beach formation. Then during the elevation of the beach 

 to a much greater height than its present level, the slow process of 

 agglutination would have been at work upon the existing blown 

 sands, and the old beach plain would have been covered with talus, 

 or " Head," near its cliff margin, the result of meteoric waste. In 

 process of time a stream channel would have been formed in the 

 part of the cliff where the talus (C) had accumulated, and the 

 gravel (D) would have been brought down and deposited on the 

 desertion of its channel by the stream. Between these two hj-po- 

 theses it is not easy to decide. 



Unless the stony loam (C) is regarded as a fluviatile dejiosit, and 



