318 Geological Society. 



cesses and the evolution of nitrogen, the author contends, on the other 

 hand, that they suggest no facts which can set aside the evidence in 

 favour of that position, which the production of ammonia within the 

 volcano itself appears to furnish. 



A letter was afterwards read, from Lieut. Freyer, R.N., addressed 

 to Charles Lyell, Esq., P.G.S., on the appearance of elevation of land 

 on the west coast of South America. 



The localities alluded to in this letter are Arica, lat. 18° 26' south, 

 the Island of San Lorenzo in the Bay of Callao, and Valparaiso. 



Mr. Freyer states, that on his first arrival at Arica he was struck by 

 finding shells, in very great abundance, at considerable heights above 

 the present level of the sea. To the north of the town the coast is 

 low, with a shingly beach and sandy plains, no rock being exposed ; 

 but he here found shells of existing species ten or twelve feet above 

 high-water mark. On the south are interesting sections, consisting 

 of innumerable thin beds of red sandstone and gypsum, resting upon 

 shale, in which fragments of fossil shells were noticed. The bold pro- 

 montory called the Mono of Arica is formed by the dislocation and 

 elevation of this sandstone to the height of about 400 feet, by a mass 

 of basalt, porphyry, and pitchstone, which pass insensibly into each 

 other. Near the summit of the Morro the sandstone contains layers 

 of a salt, consisting of chlorine 3 1 *6, sodium 3 1 '6, sulphuric acid 1 4*0, 

 lime 9*45, potash and magnesia 9*0, insoluble (silex) 4*0*. South 

 of the Morro the sandstone and gypsum beds have a small southerly 

 dip, and form indistinct terraces towards the shore. On these ter- 

 races, wherever the rock is exposed, Balani and encrusting Millepora 

 are found. At the height of about twenty or thirty feet above the sea 

 they are as abundant, and almost as perfect, as on the shore - } at up- 

 wards of fifty feet they still occur, but abraded by the sand con- 

 stantly blowing over them j and there are traces of them at still 

 greater heights. In the island of San Lorenzo in the Bay of Callao, 

 Mr. Freyer found, at considerable heights, Concholepas, Pecten pur- 

 pureas, Sigaretus concavus, with other shells, in great abundance, 

 and retaining their colour almost as freshly as those living in the ad- 

 jacent sea. Mr. Freyer states that he did not visit Conception, but 

 that he had seen cargoes of the lime made from the shells found at 

 great heights in its neighbourhood. 



With respect to Valparaiso he regrets he did not more attentively 

 examine the neighbourhood j but he says, that to the east of the 

 town the shelly beach is now far above the reach of the tides, and 

 that rocks were pointed out to him which he was assured were under 

 water previously to the earthquake of 1822. 



March 11. — A paper was first read, entitled "Description of a 

 Bed of recent Marine Shells near Elie, on the Southern Coast of 

 Fifeshire; " by William John Hamilton, Esq,, Sec. G.S. 



The author commences his memoir by describing the geological struc- 

 ture of the neighbourhood of Elie, a small fishing-town about eighteen 



* The author states that this analysis was made by his friend Major 

 Emmett, R.E. 



