E. Gfcenhj — Sa)uhto)ie Pipes. 



21 



circular pits, varying from 1 foot to 7 feet in tlianieter. The 

 margins of these having been glaciated, they open out in trumpet- 

 shaped forms, but each can be seen to he, or to have been, filled 

 with a plug of fine white sandstqne, descending into tlie Limestone 

 at right angles to the bedding. (See Figures illustrating the 

 succeeding paper.) 



These plugs can be seen in various stages of denudation. Some 

 have been worn down flush with the surrounding Limestone, and 

 some of the smaller ones have been excavated so as to leave an 

 almost empty pit or pothole with a little sandy matter in the 

 bottom. In one part of the shore, however, the plugs have been 

 left standing each in its circular pit, some 4 or 5 feet above the level 

 of the surrounding rock (Fig. 1) ; and the foreshore here presents 



Fig. 1. — Sandstoxe Pipe in Carboniferous 1;Imkstuni;, DwLii.vN Point, 

 Anglesey. Looking N.N.W. 



a most extraordinary appearance, great masses suggestive of gigantic 

 fossil corals, or of the Paramoudras of the Chalk., standing up from 

 the rocky ledges, while others, torn out by the sea, lie prostrate in all 

 directions. 



The Limestone is here the highest bed seen, but as we proceed 

 a few yards to the S.S.E. in the direction of the dip (which is at 

 about 4'^-5^) a bed of sandstone, about 2 feet thick, comes on 

 above, forming the foreshore in its turn as the beds come down ; 

 and a little further still, in a low cliff, this is surmounted by about 

 7 feet of dark shale, and this by another Limestone of ordinary type, 

 some 8-10 feet in thickness. (Fig. 2.) 



Now at the exposed junction between the piped or lower Lime- 

 stone and the overlying sandstone, there are numerous pipes, and 

 the material of their plugs can be seen in cross section to be con- 

 tinuous with that of the sandstone above. There is no sign of 



