1910-1911.] An Account of the Excursions (191 1). 375 



The following Saturday another geological excursion, under 

 the leadership of Mr T. C. Day, took place on Blackford Hill. 

 A large number of members attended this excursion, which 

 was much marred by the very wet weather which came on 

 soon after the start. Mr Day explained that Blackford Hill 

 is composed of a basic andesitic lava, and represents the last 

 eruption of the volcanoes of the Old Eed Sandstone period. 

 This lava shows on examination a marked flow structure. It 

 rests upon a bed of ashes of considerable thickness, which 

 separates it from the trachyte lava of the Braid Hills. The 

 glacial phenomena were also observed, and particularly the 

 well-known undercut crag, where the work of ground-ice was 

 first recognised in Scotland (see Plate XXVIII.) The manner 

 in which the Braid Burn is removing the glacial drift was 

 pointed out, and also the evidence of a much higher level in 

 former times. 



On the 29th of April a considerable number of members, 

 under the leadership of the Kev. D. W. Wilson, inspected the 

 British camp on the Borthwickhall estate at Heriot. The 

 party walked along the old southern road from Heriot Station, 

 and, crossing the bridge over the Heriot Water, diverged into 

 Borthwickhall grounds. This took them into a beautiful walk 

 along the water-side. A long row of Citpressus Lawsoniana 

 in flower lined one side of the walk, and on the other a row 

 of Bubus spectahilis in full bloom. The party then climbed to 

 the summit of a hill to a fine example of a British camp in 

 an unusual state of preservation. It is one of three British 

 camps in the parish of Heriot, and there are several others in 

 the neighbouring parish of Stow. Its great size is believed to 

 be due to the fact that the natives used it not only for their 

 own safety but as a place of security for their cattle. It is 

 curious that here, as in other parts of Scotland, is found a 

 chain of British camps in contiguity with a chain of Eoman 

 camps, — as if the natives had been watching, and as far as 

 possible withstanding, the advancing Eomans. The party 

 afterwards proceeded to Borthwickhall, where they were 

 kindly entertained by Mr and Mrs Macfie. 



On the 6th of May a large excursion, under the leadership 

 of Mr John Thomson, took place to Craigiehall, near Cra- 

 mond. Entering the policies at Cramond Bridge farm, the 



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