322 Geological Society : — 



For some time previous to the occurrence of a severe earthquake- 

 shock, on or about the 30th August 1857, the Bay of Payta swarmed 

 with crabs, of a kind not generally observed, and ten days after the 

 earthquake they were thrown up on the beach, in a raised wall-like 

 line, 3 to 4 feet wide, and to the height of about 3 feet, along the 

 whole extent of the bay.'and above highwater-mark. 



At the same time as the upheaval of the crabs took place, the 

 water of the bay became changed, from a clear blue, to a dirty 

 blackish-green colour, much resembling that off the Island of Chiloe, 

 Concepcion, and the southern parts of Chili. Ten days afterwards. 

 Dr. C. Forbes found that living specimens of the crabs M'ere still 

 numerous in the bay, but all appeared to be sickly, and numbers 

 came ashore to die. 



There were no appearances of any alteration of the relative 

 position of sea and land in the yicinit)% nor had any ebullition of 

 gases been observed ; although probably to both these causes com- 

 bined the phsenomenon described was due. 



February 3, 1858. — Major-Gen. Portlock, President, in the Chair. 

 The following communication was read ; — 



" On the Succession of Rocks in the Northern Highlands, from 

 the oldest Gneiss, through Strata of Cambrian and Lower Silurian 

 age, to the Old Red Sandstone inclusive." By Sir R. I. Murchison, 

 F.R.S., V.P.G.S. 



This memoir comprised a general sketch of the succession of the 

 stratified rock- masses occupying the northernmost counties of Scot- 

 land (Sutherland, Caithness, and Ross), as determined by former 

 observations of Prof. Sedgwick and the author, and of MaccuUoch, 

 Jameson, Cunningham, Miller, and Nicol, and by the recent disco- 

 veries of Mr. Peach. In the commencement, Sir Roderick, having 

 referred to the long-held opinion that the great mountainous masses 

 of red conglomerate and sandstone of the west coast were detached 

 portions of the Old Red Sandstone, alluded to Mr. C. Peach's 

 discovery (in 1854) of organic remains in the limestone of Durness, 

 which led the author to revisit the Highlands (accompanied by 

 Prof. Nicol), when having found still more fossils, he expressed his 

 conviction (at the British Association, Glasgow Meeting, 1854) 

 that the quartzites of Sutherland and their subordinate limestones 

 were of Lower Silurian age ; and was strengthened in the opinion 

 (which he had already published) that large portions of the cry- 

 stalline rocks of the Highlands would prove to be the equivalents 

 of Lower Silurian deposits in the South of Scotland. In 1856 

 Colonel James and Prof. Nicol separately observed the unconform- 

 able overlap of the great conglomei'ates by the quurtzite series ; 

 and the latter geologist greatly extended all previous observations, 

 and communicated to the Society a memoir, showing that the old 

 gneiss and its superposed conglomerate, as seen along a very exten- 

 sive region of the Western Coast, formed the buttresses upon which 

 all the crystalline (puutz-rock and limestone of the western parts of 



