176 PROCEEDINGS OP THE eEOLOGICAI, SOCIETY. [Jan. 11, 



there at various depths in the fine clay — sometimes singly, but fre- 

 quently one or two together. Now it is quite common in some of 

 the pits to find a crust of Balani attached to one of these boulders, 

 and I think it has generally been supposed that the Balani are con- 

 fined to the upper surface and sides of the stone, as if they had 

 grown upon it after it had been dropped into its present position. I 

 satisfied myself, however, that this is not always the case ; for I 

 found that Balani do occasionally occur all over the lowermost side. 

 For example, I observed one heavy stone, measuring 32 inches in 

 length (32 x 14 x 18 inches), imbedded in the clay about 15 feet 

 from the surface. This boulder had not been moved out of its 

 original position, and there were remains of Balani on various parts 

 of the surface. With the assistance of the foreman of the work, I 

 dug round it, and heaved it out of its bed, and found that the whole 

 under side of it was covered with a close thick crust of entire Balani, 

 the points of which were sticking downwards into the soft clay 

 beneath, showing clearly that they must have grown upon the stone 

 before it was dropped into its muddy bed. Other instances of the 

 same kind were observed by me in this brickwork. I conclude, 

 therefore, with regard to some of these boulders at least, that Balani 

 grew on them before they came to be lodged in the clay (probably 

 when they lay on some shore), and that afterwards they had got 

 encrusted with ice, and being floated off had dropped to the bottom 

 when the ice about them melted *. 



I noticed that these boulders, with the Balani on them, some- 

 times exhibit glacial scratches. Here, then, we have evidence of 

 three distinct events : first, the boulder was scratched ; secondly, 

 barnacles grew on it ; thirdly, it was carried off and dropped to the 

 bottom of the sea. If this transportation was due to floating ice 

 (and I do not see to what else we can ascribe it), it would therefore 

 appear that the floating ice had nothing to do with the scratching of 

 the stone. 



I by no means deny that barnacles likewise grew on the stones 

 after they had fallen to the bottom ; I have no doubt they did. 

 They also occur on some of the larger shells, such as the Buccinum 

 undatum, and I picked up a specimen of the Trophon scalariformis 

 with three attached to it. 



In this Paisley clay I sometimes found, on heaving up a boulder, 

 a number of young crushed mussel-shells beneath it, as if they had 

 been squashed by the fall of the stone. The clay around also occa- 



* I believe the species of Balanus on the under side of the boulder above 

 mentioned was B. halanoides of Darwin's monograph, for I feel pretty svu-e it 

 had no calcareous base ; but not having brought away specimens, I am unable 

 to be quite certain of this. Those I have, adliering to shells, are not this spe- 

 cies, but B. porcatus or B. crenatus. Now B. lalanoides, according to Darwin, 

 is a species that lives only between tide-marks ; if this is correct, then it could 

 scarcely have grown on stones lying in water so deep as is indicated by the 

 shells in this clay; and its presence could be explained only by some such 

 theory as I have suggested. It would be an interesting fact should the Balani 

 on the upper surface prove to be of a deep-water species, and those on the lower 

 of a tidal one. 



