ON THK SHELL-BEAEING DEPOSITS AT CLAYA, AND OTIIEB PLACES. 503 



numerous, and a few Osfcracoda were also found, leaving no doubt that 

 they belonged to the deposit. 



5. The gravel (in second tin box) taken from 2 feet below the shelly 

 clay, at east end of the ' main section,' was prepared in the usual way, and 

 lost little by washing. The stones were all well water-worn, with the 

 exception of the sandstones, most of which appeared to have been sub- 

 jected to little or no rolling. A few rootlets and two Foraminifera were 

 obtained. Although every precaution had been taken to prevent admix- 

 ture of the materials, still there are many ways in which this might occur, 

 either in the field or during examination. 



The sand from this part of the section is of a light yellowish colour, 

 and consists chiefly of small well-rounded particles of quartz with 

 some light grains of mica, derived apparently from the adjacent Old Red 

 Sandstone. In these respects it closely resembles the sand which overlies 

 the shelly clay, and differs in a marked degree from that contained in the 

 shelly clay itself, which, as already mentioned, is dark or dark-grey in 

 colour, and contains much black mica, apparently derived from the dis- 

 integration of gneissose rocks. 



BiemarTts. 



The deposit in all its aspects, taken in connection with its high level, 

 is very puzzling. Although its Arctic character is well established, it 

 differs much from any of the post-Tertiary clays that have come under 

 my notice, particularly in respect of the small variety of fossil organic 

 remains found in it, there being very few remains of echini, star-fishes, 

 worm-tubes, crab-claws, or polyzoa, which are common in the post- 

 Tertiary clays, both on the east and west coasts of Scotland. 



The shells, with the exception of those that are young and friable, 

 are fairly well preserved, and show no marks of rubbing or polishing, so 

 far as I could discover. They are chiefly of shallow- water species ; some 

 may have lived in from fifteen to twenty fathoms, but nearer the shore 

 as well ; and the great majority are undoubtedly of littoral species. 



With regard to the physical characteristics of the deposit, the follow- 

 ing points seem worthy of notice : — (1) The fineness of the sand over- 

 lying the shelly clay, and its freedom from stones or gravel ; (2) the 

 generally rounded and water- worn appearance of the stones in the clay, 

 and the small proportion of sand accompanying them ; and (3) the 

 difference in appearance and composition between the sand in the shelly 

 clay and that occurring both beneath and above it, and the fact of the 

 different parts of the deposit — clay, sand, and overlying boulder clay — 

 being so sharply defined from each other. 



The question comes to be, Have the shells lived and died where they 

 are found ? After considering all the evidence that has come under my 

 own observation I am strongly inclined to believe that they did live and die 

 where they are found . If we suppose that a transportation of the deposit 

 has been effected by ice action, it is difficult to see how the stones could be 

 so free from striation, or the sand overlying the shelly clay so fine and so free 

 from stones (those found in it being not much larger than a pea), or how 

 the different strata of the shelly clay, the sand, and overlying boulder 

 clay could be laid down so sharply defined, the one over the other, if 

 crushed up to their present position by ice in any form. 



David Robertson. 



