PROCEEDINGS 



OF 



THE GEOLOGICAL SOCIETY OF LONDON. 



1827—1828. No. 4. 



November 2. — The Society having assembled this evening for the 

 session : — 



An extract was read, of" A letter from Captain P.P. King, R.N., 

 to Dr. Fitton, P.G.S., dated at Rio de Janeiro, 10th June, 1827 : — 

 with some observations on the specimens sent home by Captain King ; 

 by the President." 



The expedition under Capt. King, for the purpose of surveying the 

 Straits of Magellan, left Monte Video on the 1 9th of November, 1826 ; 

 and after putting into Port St. Elena, about lat. 45° south, and remain- 

 ing for a day or two in the vicinity of Cape Fairweather, continued for 

 ninety days within the Strait ; during which time, its shores, to the 

 east of Cape Froward, were surveyed under the superintendence of 

 Capt. King himself ; while his consort, under Capt. Stokes, examined 

 the western entrance. The map and specimens sent to England, 

 contain the results of these operations ; and Capt. King intended to 

 sail within a short time after the date of his letter, for the purpose of 

 continuing the survey. 



The coast at Port St. Elena is described by Capt. King as consist- 

 ing of porphyritic claystone ; of which the hills, from 300 to 400 feet 

 high, are entirely composed. The specimens from thence consist 

 of claystone, compact felspar, and hyperstene rock ; and the beach 

 affords a conglomerate, consisting of rounded fragments of these 

 substances, cemented by carbonate of lime containing portions of 

 shells, and resembling the recent calcareous conglomerates which 

 abound on the shores of Asia Minor, Australia, and several other 

 parts of the world. 



Cape Fairweather is near the southern extremity of a range of 

 coast, occupying between two and three degrees on the east of Pata- 

 gonia • a great part of which is described in the Admiralty Chart, as 

 being "like the coast of Kent, and consisting of steep chalk hills,-" 

 — one of the prominences being named, from a supposed resemblance, 

 " Beachy Head." This, however, from Capt. King's statement, 

 would appear to be erroneous : — the whole coast examined by 

 him, was found to be composed of horizontal strata of clay, which 

 may be traced for several miles in unbroken continuity ; the cliffs 

 being from 300 to 400 feet in height, and entirely bare of vegetation. 

 Some of the specimens, however, from this quarter, consist of a white 

 marl, not unlike certain varieties of the lower chalk j and with these, 



