12Q T. M. READE ON THE DRIFT-BEDS OE THE 



and in some sands and gravels. It must not be lost sight of that, 

 during the submergence and emergence of the land, every river- 

 valley at every point has been at one time or other an estuary. To 

 expect under these circumstances all beds to be similar would be to 

 expect that which could never happen. Sand is found in pockets in 

 the Boulder-clay as well as in horizontal beds ; and these often assume 

 very curious shapes ; they also seldom contain stones, though the clay 

 surrounding them does. 



The sands and gravels at St. Bees which are in great force are 

 distinguished by contorted bedding, confused aggregation, and the 

 great number of included blocks and boulders. The shingle, gravel, 

 and sands are intruded or folded into each other. The underlying 

 clay is peculiarly free from stones. If we found geological subdivi- 

 sions on such grounds, what are we to do with these beds ? No one 

 has even suggested an explanation. 



As assisting to explain these Low-level Boulder-clays and sand beds 

 so puzzling to observers, I may here state that I have not seen in 

 the whole series one single example of well-defined shore-conditions. 

 No continuous section of any length ever displayed the horizontality 

 distinguishing most littoral deposits. They are all more or less arched, 

 as my sections show ; this is especially remarkable where continuous 

 thin beds of sand like that near Farnworth extend for a long distance. 

 I infer from this circumstance, as well as from certain collateral pecu- 

 liarities already described, that the beds from base to summit sub- 

 stantially represent a sea-bottom, the conditions of depth altering 

 as the land slowly subsided or reemerged. 



It is the circumstance that the beds represent conditions that are 

 not within our ken, as littoral deposits are, that has, I believe, led 

 to so much confusion. 



In a paper " On Tidal Action as a Geological cause " (Proc. of 

 Liverpool Geol. Soc, 1873-74), a collateral investigation I felt it 

 incumbent on me to make before I could properly attack the problem 

 presented by the Glacial beds, I have shown that the tide-wave, 

 unlike the wind-wave, acts at the greatest depths ; and among other 

 examples I have quoted that of the excavation or keeping open of the 

 "ditch" before referred to opposite the coast of Kircudbrightshire. 

 Other examples of almost equal force could be given. My conclusions 

 are that the long continuous beds, to some extent arched, are the 

 effects of tidal arrangement below low water ; the horizontal lami- 

 nations of the clay occasionally met with I attribute to the same 

 cause, and the short arched book-leaf laminations also. 



I have shown in Part I. that the shell-fragments found distributed 

 through the clay are, as a rule, only of such a size as a moderate 

 current could convey. The much-contorted and cross-laminated beds 

 of which the St. Bees sands and gravels are the best examples, I am 

 of opinion were laid down partly above and partly below low water, 

 like our estuary sandbanks within reach of the wind-waves. 



It is also quite evident that as the depth of the sea changed the 

 direction of the tidal currents would change also. Thus what was 

 a hollow in clay might become filled with sand, which, again, might 



