248 REPORTS OF MEETINGS FOR 1911 



chasm, whose walls were adorned with lichens and mosses, 

 relieved by patches of Sea Pink (Armeria maritima), and 

 Sea Campion [Silene maritima). Detached masses were scattered 

 seaward, some single, others in groups, but all fashioned by 

 the elements into strange and even grotesque figures, because 

 of which one group, not inappropriately, has received the local 

 name of Barn Yard. The stratified rocks, which are Greywacke, 

 belong to the formation which extends across the county in 

 a W.S.W. direction, and is ranked as lower Silurian. A 

 large fault, which extends from St. Abb's to Petticowick, has 

 dislocated the strata there, letting down the pile of old red 

 lavas, out of which the headland has been subsequently carved. 

 Close to the lighthouse are several necks of eruptive rocks, 

 marking the sites of small volcanic vents. These have been 

 forced through the Silurian rocks, and the stumps of the 

 volcanic plugs, much worn and battered by the waves, now 

 present the picturesque stacks to which so much of the 

 peculiar beauty of the coast is due. The crags on which 

 the colony of Kittiwake Gulls {Rissa tridactyla) has been 

 established, consist of andesite lavas, and are the Southward 

 continuation of those which form the main portion of the 

 headland. Following the coast-line and descending to the slack 

 of boggy ground which divides St. Abb's from the mainland, 

 the members had presented to them one of the finest pieces 

 of coast scenery to be found in any district, the Silurian rocks 

 to the West being doubled upon themselves and otherwise 

 convoluted to an almost unparalleled extent, and illustrating 

 a geological phenomenon of exceptional interest. The line 

 followed on their return did not afford opportunity for a search 

 being made for the botanical rarities of the district, e.g. : — 

 Arenaria verna, on the rocky slopes of the headland facing 

 landward ; Trifolium, arvense, on seabanks near Burnmouth ; 

 Thalictrum, minus, var. m,aritimum, and Sedum. Rhodiola, 

 in a deep fissure running to the sea, West of Petticowick, but 

 lay along a farm-service i-oad which proved the most direct 

 to the afternoon rendezvous, where the brakes awaited the 

 party. Driving through Northfield and Coldingham, where 

 the smaller section rejoined them, the members reached Aytou 

 at 4-30 p.m. 



