334 Proceedings of the Royal Physical Society. 



flags are truncated on tlie north side by a small fault which 

 brings down the overlying sandstones. The greater portion 

 of Eday and the whole of the Calf of Eday are occupied by 

 these sandstones. Perhaps the finest exposure of the series 

 is to be seen on the Eed Head of Eda,y (209 feet), which forms 

 the northern promontory of the island. These strata form 

 prominent hills in the centre of the island, whose features are 

 totally different from those characteristic of the Flagstone 

 series in Westray. As a rule the beds are extremely coarse- 

 grained, and frequently conglomeratic, with much false bed- 

 ding ; indeed, as we have already remarked, they have a strik- 

 ing lithological resemblance to the Upper Old Eed Sandstones 

 of Hoy. 



Southwards from the Kirk of Skail, along the shore, there 

 is a steadily descending section of the flagstones for nearly a 

 mile and a half. There is no great thickness of strata ex- 

 posed however, as the • coast line forms only a very small 

 angle with the line of strike for some distance. North of 

 Veness the Flagstone series is abruptly terminated by a fault 

 which brings down the overlying sandstones to the west. 

 This dislocation runs in a north and south direction, and 

 passes out to sea to the west of the Veness promontory. 

 There is therefore a small detached area of the arenaceous 

 series in the south-east corner of the island. 



In the island of Sanday the thick sandstone series of Eday 

 and the underlying flagstones are repeated partly by foldings 

 and dislocations of the strata. Along the western shore 

 between Spurness and Stranquoy, the grey flagstones are ex- 

 posed interbedded with red and grey sandstones which are 

 conglomeratic in places. These beds are inclined to the west 

 and north of west at angles varying from 50° to 70°. The con- 

 glomeratic sandstones and red shales interbedded with the 

 flags are seen on the western shore, about a mile to the north 

 of Spurness. It is highly probable, therefore, that the strip 

 of the Flagstone series, extending from Spurness to Stranquoy, 

 is on the same horizon with the flags, which immediately 

 underlie the Eday sandstones. 



The strip of the Flagstone series now referred to is bounded 

 on the east by a dislocation which brings in the Eday sand- 



