40 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



and wasting influence of the next flowing sand-bearing tide, wliich 

 quietly deposited a portion of its burden over the mud-coated beach ; 

 and this quiet action must have been continuous for some time, or 

 the moveable shore would have been easily deprived of every distinct- 

 ive trace. Thus there must have been a tidal beach-line, with clay 

 or mud strata, to be wasted by high tides or local storms ; and 

 neighbouring sand-banks to form an extensive sandy beach during 

 low tides and quiet weather. 



