GEOLOGY. 319 



XEW SALIXE DEPOSIT FEOM SOUTH AMERICA. 



At a recent meeting of the Boston Society of Natural History, Mr. N. II. 

 Bishop presented some samples of a peculiar crystalline salt which lie had 

 brought from South America, with the following account of the same : 

 It is found mixed with the soil in greater or less abundance, from San Luis 

 de la Punta (a town on the western side of the pampas of the Argentine 

 Republic, where the grass plains properly end and the travesia or desert com- 

 mences) to the foot of the Andes. 



San Luis lies in lat. 33 deg. 16 min. S., long. 66 deg. 27 min. "W., and is 

 the capital of the province of the same name. From this town, westward, 

 the soil is almost worthless, until the river Mendoza is reached, where irriga- 

 tion commences. 



The soil is very light and dry, not compact in the least. This is probably 

 caused by the dryness of the atmosphere and absence of water ; for when 

 Mr. Bishop crossed that part of the country, they were obliged to purchase 

 water that had been caught in holes for the use of cattle. Stones are rarely 

 met with ; where they do exist, at the base of the Andes, he did not observe 

 the existence of this salt. There are several spots on the travesia, between 

 San Luis and Mendoza, furnishing a poor quality of grass, which is fed upon 

 by the cattle which are driven across the continent to the coast. "With the 

 exception of these spots, the country between the above named towns, and 

 extending many leagues to the north and south, is a dreary desert, covered 

 with a low growth of thorn bushes and a few species of gnarled trees, some 

 of which bear pods. 



This substance penetrates the earth from a few inches to a couple of feet. 

 It is particularly abundant at certain places east of the town of San Juan, 

 where the ground is covered with a thin incrustation. It is here exceedingly 

 painful to the eyes from the reflection of the sun's rays, and the inhabitants 

 are constantly affected with inflammation of the eyes. 



The method of treating the soil by the natives is very simple. The water 

 is conducted from the rivers Mendoza and San Juan (which take their rise in 

 the Cordillera) through a sequia or canal, around squares of level land, at 

 irregular intervals of time, and, to use their own expression, they wash off 

 the salitre. Then a plough, constructed of two pieces of wood, is brought 

 into service, and turns up from six to eight inches of the soil, which goes 

 through the same washing process as the first. After two or three repetitions 

 of this operation, a shallow soil is obtained, partially free from salitre, in 

 which wheat, clover, pumpkins, melons, etc., are raised. The remaining 

 salitre. according to the belief of the natives, is exhausted by successive crops, 

 and after several years of tillage, the soil is suitable for the vine. Oranges, 

 peaches, quinces, olives, figs, etc., flourish. "Within a few years large tracts 

 of land have been made exceedingly fertile by the process above described, 

 and could the New England plough be introduced there, the process would 

 be far more valuable. 



Dr. A. A. Hayes communicated the following as the results of his analyses 

 of the saline mineral presented by Mr. Bishop. 



