The Old Bed Sandstone of Orkney. 333 



the overlying arenaceous series is observable on the east 

 coast near the Kirk of Skail, and to the north of Warness, 

 which forms the south-western promontory. Owing to the 

 synclinal fold in the strata, the flagstones at Fara's Ness are 

 brought to the surface again at Warness, and these beds are pro- 

 longed in a north-north-easterly direction towards the Kirk of 

 Skail. At both of these localities grey and white sandstones 

 are interbedded with the flags, and these pass upwards into 

 conglomeratic red and yellow false-bedded sandstones. 



The section exposed on the beach at Kirk of Skail and 

 on the south side of Lonton Bay, exhibits the following suc- 

 cession in descending order : 



Red and yellow sandstones. 



Flagstones, 40 feet. 



Reddish shales, . . . . 15 ,, 



Hard white sandstone, . . . 20 ,, 

 Grey calcareous flagstones. 



The sandstones at the top of this section are flaggy at their 

 base, but become more massive and conglomeratic upwards. 

 The included pebbles consist of fragments of mica schist, 

 quartzite, gneiss, granite, and other metamorphic rocks all 

 stained of a reddish colour. The occurrence of these pebbles 

 tends to confirm Professor Geikie's expressed opinion that 

 the Lower Old Eed Sandstone strata of Orkney were laid 

 down on a very uneven surface of the older crystalline rocks ; 

 for an exposure of these latter must have still existed at no 

 gTeat distance, when the highest beds of the Lower Old Eed 

 Sandstone series now preserved in Orkney were being 

 deposited. 



In the bay to the north-east of Stenniehill a zone of grey 

 flagstones with fish remains is interleaved with the sandstones, 

 as we found to be the case on the west side of the island in 

 the bay of Fara's Ness. This zone can be traced at intervals 

 across the island in a south-westerly direction to the coast 

 line west of the Wart of Eday. 



About half a mile to the south of the entrance to the CaK 

 Sound, the base of the arenaceous series is again exposed on 

 the coast line. The gTcy and rusty flags form a low arch on 

 which the coarse-gTained sandstones rest conformably. The 



