1894-95-] Geological Notes from Arran. 123 



vention of Cruelty to Animals about once a-year, but he ap- 

 pears to prefer paying the fine and keeping bad horses as being 

 the more profitable course to pursue. Under the circum- 

 stances, I hired a conveyance for the day, which had the 

 advantage of my being able to keep it waiting at any con- 

 venient point of interest. On the way to Blackwaterfoot we 

 pass two districts where granite occurs among strata of un- 

 doubted carboniferous age. Both granites have the same 

 structure, and are of a peculiar appearance, hardly looking 

 like the rock that generally bears that name. The interest 

 attaching to them is that they are considered to be of Tertiary 

 age, and are, so to speak, very young granites. I believe the 

 main evidence in support of their age is that they very closely 

 resemble granites of the Tertiary period found in other dis- 

 tricts. The eastern patch is called the Ploverfield granite, and 

 the western the Craig Dhu granite. I do not know whether 

 their relation to the great granite nucleus has been made out, 

 but in certain districts of the great nucleus there occur large 

 masses of a fine-grained granite very similar in structure to the 

 granites of Ploverfield and Craig Dhu. This fine-grained 

 granite is supposed by some geologists to have been intruded 

 into the general mass of the much coarser granite, and there- 

 fore to be of considerably later date. I did not have an oppor- 

 tunity of inspecting the fine granite of the nucleus, and am 

 not therefore in a position to offer an opinion as to the con- 

 nection between it and the granites of Ploverfield and Craig 

 Dhu. At a spot near Glen Loig bridge, which crosses Glen 

 Craisag Water, and high up in the hills to the south of the 

 road, there is to be seen an old limestone quarry. The lime- 

 stone is of a hard crystalline nature, and has been much meta- 

 morphosed by the intrusion of a mass of quartz felsite. The 

 two rocks are to be seen fused together. It is difficult, how- 

 ever, to get a specimen showing this well, as there is a 

 tendency to fracture at the junction under the hammer. 

 However, after half an hour's work, I managed to secure a 

 fair example. 



On arriving at Blackwaterfoot a stroll may be taken along 

 the shore to Drumadoon Point, where a large dyke runs out 

 to sea. This dyke is composed of a rock which I have termed 

 felspar and quartz porphyry : it is composed of a grey ground- 



