THE OLD RED SANDSTONE OF THE ORKNEYS. 409 



succession between the lower and the upper series is a perfectly conformable one. An 

 extension of this syncline occupies Spurness, the S.W. corner of Sanday, and the Calf of 

 Eday. It stretches southwards into Shapinshay, where it forms the south-east corner of 

 the island. These beds have mostly a south-east dip, and belong to the west edge of the 

 syncline. Thence it extends into the opposite shores of the Mainland, and occupies an 

 area which stretches from Holland Head around the shores of Inganess Bay and in a 

 narrow strip to the Skerry of Yinistay in Tankerness. The west boundary of this is 

 a considerable fault already described as seen in the south-west corner of the bay, on 

 the old Kirkwall road, and running thence along the shore and by Berstane House to 

 the centre of the Bay of Meil. On the eastern boundary the sandstones pass perfectly 

 conformably downwards into the flags. 



The second area of these rocks is that of Deerness, first described by the present 

 writer in a previous paper. It is separated by the Tankerness anticline from the 

 Inganess Bay area, and the Bousay flags appear on the west corner of Deerness, near 

 Mirkady, and pass up conformably into the John o' Groats beds. The whole area forms 

 a well marked syncline, which includes almost the whole of Deerness, and stretches thence 

 into Holm, where a narrow area of these rocks surround the farm of Stembuster. The 

 dips throughout the south-east half of the sandstones of Deerness are south and south- 

 east. At Stembuster the south-east dips gradually swing round to E.N.E., and finally 

 to nearly north, near the Castle of Claisdie. Several faults occur in the area, one at the 

 Mull head letting down the red and yellow sandstones against the grey flags, which at 

 Sandside contain Asterolepis, sp. nov., and Dipterus valencienesii (Sedgw. and Murch.), 

 but none of the John o' Groats fossils. These flags in turn, as we pass southwards, 

 graduate upwards into the yellow sandstones. Another fault must run into Newark 

 Bay (though not seen, the area being occupied by blown sand), for to the east of it the 

 dips are south, while to the west the dips are mostly E.S.E., and the yellow sandstones 

 of one side strike at the red beds on the other. Much of this syncline must lie out to 

 sea, and possibly, as already suggested, the red rocks of Stronsay are really part of it, 

 though it is worth mentioning that the rocks of Copinshay are grey flags, undoubtedly 

 belonging to a lower horizon. 



In the south isles of Orkney the sandstones occupy the centre of the basin.* A 

 narrow strip of sandstones bound Scapa Bay from Orphir Kirk to near Scapa Distillery 

 and thence along the eastern shore to Howquoy Head, in Holm. They form the west 

 end of Bousay and the island of Hunda, here dipping west, the north-west corner of 

 South Ronaldshay, with a general north-west dip ; and on the east side, at Wind wick and 

 St Peter's Church, small areas of sandstones are faulted down among the flags of the 

 south and east side of the island. In Flotta they occupy principally the northern half 

 of the island and the adjacent Calf of Flotta, having here a north dip, and passing down 

 conformably into the grey flags of the southern shore, t Lastly, in the island of Hoy 

 they are found in that part of Walls to the north of Longhope, around the Burn of Ore, 



* Peach and Horne, op. cit., pp. 11 and 12. t Peach and Horne, op. cit., p. 12. 



