Geological Notes. 361 



their age, the bases of each being at a higher level than any of 

 the well-marked raised beaches of the country, as also the pre- 

 sence of boulder clay above and below and all around it makes 

 it, I think, certain that they are of pre-glacial origin. 



Arbigland Shore. 



On the subject of this short paper there is no pretension of 

 any original observation. But simply to offer a few notes of a 

 walk along the shore on two occasions, and aided in this by the 

 " Official Explanation of Sheet 5 " of the Geological Survey Map. 

 As seen standing on the top of the Twenty-five-Foot Beach close 

 to the Arbigland grounds and looking down on the shore, below 

 high-water mark, we see a horizontal section of what in carboni- 

 ferous times was an atoll or coral island, which has been planed 

 flat down by the action of the waves and other denuding 

 agencies, affording good illustration of the deposit and growth of 

 the original coral island, now merged into coralline limestone. 

 Looked at from above it will be seen that these coral stones form 

 a symmetrical basin, and that their successive beds are arranged 

 in consecutive layers, and, when observed nearer, they will be 

 seen to dip towards the centre at gentle angles. It can only be 

 said further that the corals to be found along the shore are 

 abundant and well preserved, also many shells, bivalves, 

 gastropods, etc., all very interesting. According to the official 

 account, on "the shore between Hogus Point and Carsethorn there 

 is an almost continuous section of carboniferous strata, all much 

 faulted and folded, which may be grouped in descending order: 

 (i) Coralline limestone of Arbigland Bay; (2) sandstones and 

 shales and marine limestones ; (3) sandstones and shales, marine 

 bands and cement sandstones." The great ice-borne granite 

 boulder is a well-known object of interest on the Arbigland shore. 



As we are not very far from Criffel, we may notice, in con- 

 clusion, that Sir Archibald Geikie, formerly Director-General of 

 the Geological Survey, has observed that " while tracing the 

 glaciation of the region, Dr Home obtained proofs that the ice 

 which drained from the inland country was in mass sufficient to 

 override Criffel, and must, therefore, have had there a minimum 

 thickness of 2000 feet. This is a fact of much interest, in view 

 of the wide distribution of boulders of Criffel granite over the 

 north of England, and even as far south as Wales." 



