854 
Proceedings of the Royal Society 
blocks of stone, foreign to the rocks of the island, viz. , Conglomerates, 
granite, syenite, chalk, oolite, limestone, and sandstone. 
In Eonaldshay boulder clay, containing these blocks, there are 
fragments of Oyprina Islandica, Astarte^ Dentalium^ and other 
marine shells. 
The Conglomerate boulders are supposed to have been carried 
from the adjacent island of Sanday ; the blocks of granite and 
syenite from Stromness and Pomona, distant about 45 miles to 
S.W. 
Messrs Horne and Peach {Journ. of Lond. Geol. Soc. for Hov. 
1880) mention that in Stronsa Island (not far from Eonaldshay) 
there is a bed of clay, 20 to 30 feet thick, containing granite, gneiss, 
oolite, and chalk flints, &c., all foreign to the island, besides frag- 
ments of marine shells. 
Mainland. — Mr Miller of Ben Scarth reports a valley bissecting 
the island, which he thinks was formerly an arm of the sea. 
The lochs of S tennis and Stanay now occupy it. 
Ho large boulders ; but on north exposures of hills there are 
small stones strewed over the surface, quite different from rocks in 
situ. The former are chiefly white freestone ; the rocks Old Eed 
Sandstones or flagstones {Second Report, p. 167), 
Messrs Peach and Horne express an opinion that all the 
boulders in the Orkneys, as well as in the Shetlands, were carried 
or pushed across the islands by a Scandinavian ice sheet from the 
S.E. 
Objections to that theory were suggested by the Convener, in 
articles which appeared in the Geological Magazine for 1881, and 
in an address by him to the Edinburgh Geological Society in May 
1881. 
In addition to the foregoing notes respecting Orkney boulders, 
it is proper to notice the researches of Messrs Peach and Horne. 
In a paper, published in the Journal of the London Geological 
Society for Hovember 1880, it is mentioned, as the result of their 
survey, “ that the islands have been glaciated in one determinate 
direction, independently of their physical features. When we con- 
sider that the glaciated surfaces along the cliff tops, as well as the 
roches moutonnees on the hill-slopes, prove that the islands must have 
been overflowed hy ice, we cannot resist the conclusion that the ice 
