The Old Bed Sandstone of Orkney. 331 



The results of oiir observations confirm the statements we 

 have just quoted from the papers of Professor Geikie and 

 Professor Heddle. In the course of our recent traverses we 

 examined nearly the whole of the coast line of Westray, 

 Sanday, Eday, Stronsay, Shapinshay, South Eonaldshay, and 

 the Mainland, a portion of Hoy, and some of the small islands of 

 the group. The succession of the strata is more clearly defined 

 in the northern islands, and we shall therefore begin by de- 

 scribing the relations of the Flagstone series as they are 

 exposed on the coast sections of Westray, Eday, and Sanday. 



Along the western shores of Westray there are admirable 

 sections of grey and rusty-coloured flags, dipping in a westerly 

 direction at a gentle angle. The bluff cliff of the Noup 

 Head (about 240 feet) in the north-west corner of the island, 

 consists throughout of finely-bedded rusty-coloured flags ; and 

 similar strata are met with on the slopes of the Fitty and 

 Gallow Hills, to the south-west of Pierowall. The remark- 

 able terraced appearance which these hills present when seen 

 from Pierowall or Cleat, is characteristic of the flagstones. 

 This feature is due to the denudation of softer members of 

 the series, which must have been mainly accomplished in 

 pregiacial times. This is evident from the occurrence of 

 polished surfaces and ice markings in many of the successive 

 ledges on the hill slopes. 



At ISTethergarth, in Tuquoy Bay, the flagstones roll over to 

 the east, and this easterly dip continues, with some gentle 

 undulations, along the south-western shore to the promontory 

 of Eapness. And so also along the eastern shore from New- 

 ark by Eackwick, Stangar Head to Weatherness, the grey and 

 rusty flags are inclined to the east and south of east. The 

 same easterly dip is observable on the southern promontories 

 of Papa Westray. It follows, therefore, that we have a low 

 anticlinal arch with several minor foldings in the island of 

 Westray, the axis of which crosses the island from Tuquoy 

 Bay northwards in the direction of the western shore of 

 Papa Westray. The flagstones exposed in the south-eastern 

 part of the island are merely the repetitions of those met 

 with in the western portions. 



As we approach Weatherness, which forms the south- 



