:?94 MR JOHN S. FLEXT ON 



Peach and Horne *). Along the shores of the Stenness Loch from Onston to below 

 Deepdale, the same phenomena are repeated. Yet in this district the amount of actual 

 crushing and fracture is much less than on Tenston Ness, and there can be no doubt 

 that the throw of the fault is rapidly diminishing as it passes south. Similarly, to the 

 north, on the shore of the Harray Loch at Kirkness, these appearances are repeated, and 

 no doubt the fault runs northward to the west of Dounby village, though here not 

 easily traceable, owing to the thick boulder clay sheet which covers these low grounds. 

 Here, too, it is dying out, and no trace of it is to be found on the north shore of the 

 Mainland. 



Continuing our traverse across this fault, we find that the persistent west dips 

 practically cease at the Standing Stones, where, for a time, the beds are gentty rolling, 

 and they are last seen in the quarries to the north-west of Maeshowe. In all Harray 

 the dips are gently eastwards, except on the shore of the loch at the Point of Ness, and 

 these east dips continue through the whole of the range of hills which, starting at 

 Finstown, runs northwards to Costa Hill in Evie, and separates the parishes of Birsay 

 and Harray from Evie, Kendall, and Firth. Similarly, in Greenay Hill, Birsay, in 

 Hunland, and in the hills to the east of the village of Dounby, the easterly dips prevail. 

 It is only in the extreme east of the Mainland, in Woodwick, Evie, in Rendall, and in 

 several places along the shores of Firth Bay, that this direction is reversed, the rocks 

 of this district having in many places a very gentle inclination to the west, and forming 

 thus a little marked syncline. 



Such being in its main features the structure of the West Mainland of Orkney, we 

 would naturally expect to find the Sandwick and Stromness beds repeated on the 

 eastern limb of the anticline in Harray and Stenness. This, however, is not the case, 

 as the richly fossiliferous beds on the west side of the Stenness lochs do not reappear on 

 the east, where the rocks in many points resemble the Rousay beds of the North Isles 

 and the East Mainland. They are comparatively poor in fossil remains, and have never 

 yielded, to my knowledge, the type fossils of the Stromness zone. This is, there can be 

 little doubt, the effect of the north and south fault, which has let down these compara- 

 tively barren beds against the Stromness series which encircles the granite axis. It is 

 only in the northern part of this area, at Dounby, Greenay Hill, and other localities in 

 Birsay, that the fossils of the Stromness beds are to be found in quarries with an 

 easterly dip, and here the evidence points to the theory that the fault is rapidly dying 

 out, as it passes northwards to the west of Dounby. The Firth and Harray beds may 

 be, in consequence, relegated to the passage beds between the Stromness and the Rousay 

 series of the Old Red of the Orkneys, and seem to be on the same horizon as those which 

 occupy the wide area which stretches from Stenness, through Orphir, into Kirkwall. As 

 we shall see later, when we continue the section through Rousay and Egilshay into the 

 Eday sandstones, we have a constantly ascending succession ; and as nowhere do the 

 Stromness fossils recur, the inference is obvious — as might have been anticipated from 



* Peach and Horne, Old Bed Sandstone or Orkney, p. 10 



