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REV. THOMAS BROWN ON THE ARCTIC SHELL-CLAY 



sandstones of the district. The shell-bearing clay is well laid open, occupying 

 the whole side of the brickfield, where it shows the following series : — 



Section I. 



Fig. 1. 



1. Immediately beneath the surface a yellowish or brown clay, from 5 to 8 feet 

 thick, lighter in colour, and less compact in structure than the underlying beds. 



2. A black band of particularly fine clay, a foot or rather less in thickness. 



3. An underlying deposit of dark-red tenacious clay, from 5 to 8 feet in 

 depth. 



4. The boulder-clay or till, on which all the above beds rest. Its uneven 

 surface shows that it had been denuded, and there is a marked line of separation 

 between it and the next bed above. 



The whole of this series contains boulders and stones, from the size of a 

 marble up to masses of very considerable weight, some of the largest being 

 found near the top of the section. The clay itself is particularly fine, but it 

 requires much care to free it from stones, — every separate portion, as it goes 

 through the machine, requiring to be hand-picked. The fossil shells are found all 

 through the three highest beds. In No. 2 they are particularly abundant, the 

 blackness of the bed being due to the decay of animal matter. They are also 

 very plentiful near the bottom of No. 3, where they are found clustering around 

 and beneath the enclosed boulders — a fact which seems to show that at the time 

 these shells lived this part of the sea-bottom must have been swept by a strong 

 current, and they had found it convenient to shelter themselves under the lee of 

 the stones. 



The shells themselves are in beautiful preservation. Though sometimes frac- 

 tured by pressure or shrinkage, yet the epidermis and other parts are usually as com- 

 plete as if they were recent. They soon crumble on exposure to the air. I shall 

 afterwards refer to the species, and to the skeleton of a seal found along with 

 them. 



The position of the three sections at Elie will be understood by referring to 

 the accompanying sketch map. (Plate XXXVII. ) 



