THE OLD RED SANDSTONE OF THE ORKNEYS. 399 



the Rousay beds on the east side of the Eday syncline, though as yet they have not 

 yielded the characteristic fossils. In the same group must also be placed the North 

 Ronaldshay flags, which time did not permit me to visit and examine in detail. Pro- 

 fessor Heddle tells us that here the east and west dips are about equally common.* 

 The island of Stronsay, which lies to the south of Sanday, has on the whole a similar 

 structure. It consists for the most part of flags, with one or two areas of John o' Groats 

 sandstones in the south and south-east. The dips along Linga Sound and the north-west 

 side generally are to the north-west, while on the south side, near Housebay, they roll 

 over to the south-east (sect. 2). The structure is thus an anticline like that of the more 

 northern island. I was not able to obtain any data as to the fossils they contain. 



In Westray, as Peach and Horne t remarked, the structure again is an anticline, 

 though a careful examination showed it was not a simple one (sect. 2). The axis runs from 

 Garth in Tuquoy Bay, to the Sneuk on the north shore. To the west of this, the flags 

 have a persistent though gentle dip to the westward, only reversed for a short space at 

 Noup and Noup Head. To the east of this line the flags form a rolling series, as is well 

 seen along the south shore, where two or three small anticlines and synclines succeed one 



Eday. Stronsay. 



Section 2. — N.E. and S.W. from Noup Head (Westray) to Lamb Head (Stronsay). 3 miles = 1 inch. 



another. On the north shore, the dips are similarly rolling. From the Point of Tafts 

 along the west shore of Rackwick runs a line of dislocation already mentioned as 

 probably a continuation of that seen in Egilshay, and in Rapness the dips are mostly 

 east, though in the extreme south end the flags on the western shore have a west dip. 

 If we neglect the fault, the same strata are thus constantly repeated. There is no 

 doubt they are the same as those of Rousay and of Sanday, the structure being only a 

 continuation northward of that already seen in the northern shore of Rousay. The 

 fossils I found there were Glyptolepis paucidens (Ag.), Homosteus Milleri (Traq.), 

 Dipterus valencienesii (Sedgw. and Murch.), Osteolepisl Estheria membranacea. 



In Shapinshay we have the two series of rocks — the Rousay beds in the north and 

 west, and an area of Eday sandstones in the south and east. On the east side the 

 beds have a strong south-east dip, but on the north-west corner, around the Gait and 

 in Veantrow Bay, the dips roll greatly, and this is probably the effect of a series of 

 faults which disturbs them : one seems to run from the Gait in the north to the Telegraph 

 hut near Elswick on the south, while the fault which starts at Howquoy Head and runs 

 under the town of Kirkwall must pass just to the west of the shore of the island. As 

 lias been pointed out by Peach and Horne,| the area of sandstones on the south-east 



* Heddle, op. cit., p. 122. t Peach and Horne, op. cit., p. 2. J Peach and Horne, op. cit., p. 9. 



VOL. XXXIX. PART II. (NO. 13). 3 P 



