Over the Plain of Cumberland. 565 



ridge to the soutli-east wliich is situated near to the sea-coast, the 

 boulders are the most numerous. They generally occupy positions 

 in which they may have been left by grounding ice-floes. The 

 granite is much the same throughout the whole area over which it 

 has been dispersed. Where the lai'ge boulders are most numerous, 

 at least five out of six are of a very coarse-grained light-coloured 

 or grey granite, with crystals up to three-fourths of an inch 

 in breadth and two inches in length. It often presents a more or 

 less i-eddish tinge, when it looks somewhat like Shapfell granite, 

 from which, however, it is structurally distinct. It is undoubtedly 

 the same as the granite found in situ along the southern base of 

 Criffell, and there it occurs in cliffs, as well as in block-strewn 

 slopes, from which the boulders may readily have been launched. 

 Next to the lai-ge-crystalled granite, a grey variety resembling the 

 granite now quarried near Dalbeattie, on the north-west side of 

 Criffell, is the most abundant. I have found it as far east as Nether 

 Welton. Connected with this variety, and often graduating into it, 

 there is a dark, streaked, or semi-gneissose granite. The above 

 three varieties are characterized by dark blotches or patches, up to 

 two or three feet in diameter, which in some instances look like 

 fragments of whinstone caught up in the once-molten mass, in others 

 like the effect of a. process akin to segregation. These blotches are 

 characteristic of the Dalbeattie and Criffell granite in situ, and are 

 of themselves sufficient to indicate the derivation of the erratic 

 blocks. The largest blocks of granite I have seen, which have evi- 

 dently been transported from the Scottish side of the Solway Firth, 

 are on the beach near Flimby. There are four near to one another, 

 and each is about 8^ x 7 x 3 feet. 



In addition to the above varieties, there is a hard, reddish, coarse, 

 syenitic granite, very abundant on the sea-coast among the smaller 

 stones, and extending to the innermost boundaries of the granitic- 

 drift area. I have not yet been able to trace its derivation. Mr. 

 Mackenzie, of the Creetown Granite Works, near Wigtown, informs 

 me that he has found it, in the shape of boulders, in his neighbour- 

 hood, along the sea-coast, and up the bed of the Cree, growing 

 coarser and not so red near Cairnsmore. He has also found a small 

 boulder of red, large-crystalled granite, in drift, at the Fell Granite 

 Works. The Fell granite in situ, is fine-grained and nearly white, 

 with about one-eighth part of black mica. In the granite of Bagbie- 

 bar quarry, about a mile farther south, and near the sea, about one- 

 third part is black mica. Both these granites, I believe, are repre- 

 sented in the Cumberland drift, especially among the smaller stones 

 and boulders.^ 



The principal facts above stated can, I think, be explained, in no 

 other way than by supposing that the granitic boulders of Cumber- 

 land were derived from the opposite side of the Solway Firth. From 



^ Accompanying the granitic drift, especially on the sea-coast, there are numerous 

 pebbles, and occasional boulders of dark, hard, fine-grained whinstone, which would 

 appear to have come from the Scottish side of the Solway Firth, where, in many 

 places,, it is the prevailing rock. 



