ifSS Geological Society. 



The vicinity of Mount Tarn and Eagle Bay, about midway between 

 Port Famine and Cape Froward, affords also porphyritic and crystal- 

 line rocks, abounding in hornblende, or hyperstenej with grauwacke, 

 siliceous slate, and gray splintery limestone. The slate of Mount 

 Tarn contains traces of organic remains. — The specimens from the 

 south side of this eastern branch of the Strait consist of mica-slate 

 approaching to gneiss, found at the entrance of St. Magdalen's Sound ; 

 and at Card Point on the south-west of St. Gabriel's Channel. The 

 rocks at Cape Waterfall near Card Point, are of clay-slate ; and the 

 shores of Admiralty Sound afford granite and various porphyritic rocks ; 

 including clinkstone-porphyry, and greenish compact felspar. Capt. 

 King mentions his having observed also reddish quartzose-sandstone, 

 resembling that of the old-red-sandstone formation of Europe : and he 

 remarks, that the soil over this rock is barren, while that above the slate 

 produces luxuriant vegetation ; beeches of great size growing there 

 within a few feet of the water-side. In general, the hills in this part 

 of Terra del Fuego appear to be of slate : they rise to the height of 

 3000 feet, and are covered with snow and ice. Mount Sarmiento, 

 liowever, which is more than 5000 feet high, appears, from the shape 

 of its summit, to be volcanic ; and was called by the navigator, 

 after whom it was named, " The Snowy Volcano." 



The specimens sent by Capt. Stokes from the western branch of 

 the Straits of Magellan, all consist of primitive rocks : Cape Notch, 

 Cape Tamar, and the Scilly Islands affording granite ; Port Gallant, 

 and Cape Victory, gneiss and mica-slate ; and Valentine's Bay, clay- 

 slate much resembling that of Port Famine, These places are all on 

 the north of the Strait. On the southern side, in Terra del Fuego, Cape 

 Upright affords granite and gneiss ; and the latter rock is found also at 

 Tuesday Harbour, and in the neighbourhood of Cape Pillar : the co- 

 lumnar mass, from which that remarkable point was named, is com- 

 posed of mica-slate. 



Of the specimens sent by Capt. King from this remote quarter 

 of the globe, it may be remarked, in general, that they agree perfectly 

 with the rocks of Europe and other parts of the world ; — the resem- 

 blance amounting, in several cases, to almost complete identity. 



The reading was begun of a paper " On the Geology of Tor and 

 Babbacombe Bays, Devon j" by H. T. De la Beche, Esq. F.R.S. &c. 



Nov. 16. — The reading of Mr. De la Beche's paper, begun at the 

 last Meeting, was concluded. 



The coasts of Babbacombe and Tor Bays are composed of new red 

 sandstone, carboniferous limestone, old red sandstone, and trap- 

 rocks : and the sections presented by the cliff's exhibit various marks 

 of disturbance, which the author conceives to have been caused by 

 the intrusion of trap among the strata subsequently to their deposition. 



1 . The new red- Sandstone here consists of red conglomerate re- 

 sembling that of Heavitree and Exeter, being made up of portions of 

 old red sandstone, carboniferous limestone, shale, quartz, graywacke, 

 and porphyry, with small crystals of felspar :— the whole cemented by 

 a red paste, and occasionally interstratified with red sandstone and 

 marl. The conglomerate is regarded by the author as the lowest 

 part of the new red sandstone formation, and as the equivalent of the 



Tothe 



