John Smith — The Great Submergence. 501 



The fossils from the shelly clay may be tabulated as follows : — 



Species. 



Mollusca 24 



Decapoda ... ... ... ... 2 



Cirripedia ... ... ... ... 1 



Ostracoda ... ... ... ... 24 



Annelida ... ... ... ... 1 



Foraminifera 36 



Total ... ... 88 All marine .species. 



I will now give my own interpretation of the Clava section, 

 commencing with the lowest bed. 



Bed No. 5 is described as " brown clay and stones," and is 

 probably the Lower Boulder-clay, but as it is only known from 

 boring, nothing further need be said about it. 



Bed No. 4 is composed of coarse gravel and sand. I shall call 

 it the basal gravel of the Interglacial Period, and explain my reason 

 for this. When a country is sinking below the sea, the shore waves 

 constantly agitate the material they come in contact with, washing 

 out the mud aud forming gravels and sands. These may in 

 time form what are known as basal conglomerates, from being 

 found at the bases of the great formations. This bed, then, I take to 

 have been formed by the waves when the land was sinking. It may 

 originally have contained abundance of shells, etc., but in such loose 

 material fossils are seldom preserved. 



On the top of it comes the shelly clay, 16 feet in thickness, with 

 stones up to six inches in diameter, mostly in the lower part. It 

 has no stratification, no bedding-planes; the stones cannot, then, 

 have been rolled into it by bottom currents. 1 If they had been 

 so derived it would have been a gravel bed instead of a mud bed 

 with stones ; currents strong enough to have rolled along stones 

 from two to six inches in diameter would have swept away all the 

 muddy material. 



The shelly clay has been formed in deep water by surface currents 

 carrying muddy water, and thin shore-ice carrying mud, sand, 

 stones, and littoral species of shells. It also contains ten species of 

 shells that may have lived at a depth of 150 fathoms ; and as 

 many of those which have lived at moderate depths may have been 

 cast ashore and caught up by the shore-ice which carried the 

 stones, there is no difficulty, in this view, of seeing how shells 

 which lived at different horizons may have been commingled in 

 the Clava shelly clay. 



The next bed is composed of fine stratified sand, with some very 

 small stones. It is 20 feet in thickness, and is yellowish-brown in 



1 At a depth of 3^ feet in the clay a horizontal line was observed, and at 6 or 7 feet 

 streaks or thin layers of sand and" gravel were seen, but these do not at all affect 

 the argument. There was also a transition bed of 2 ieet in thickness at the bottom 

 of the shelly clay, with a well-defined bedding-plane between it and the gravel bed 

 below, the 2 feet bed being mixed with fine gravel. 



