Trans. N. V. Ac. Set. 90 Feb. 12, 



zite or its relative, gmelinite. Some good bits of Blende are worthy of 

 preservation. 



No allusion need be made to thomsonite, unless the name be applied 

 to certain mysterious specimens, the nature of which has not yet been 

 determined. The crystals are acicular, ot remarkable length, radiating 

 from a globular nucleus of considerable hardness. 



Pyrtte, in brilliant and finely modified crystals, was brought out plen- 

 tifully from Shaft No. i. Some of the finest of these were half an inch 

 in diameter. 



The subject was further discussed by Mr. Kunz and the Chair- 

 man. 



Dr. John S. Newberry then read the concluding part of his 

 paper on 



THE BOTANY AND GEOLOGY OF THE COUNTRY BORDERING THE RIO 

 GRANDE, IN TEXAS AND CHIHUAHUA. 



(Abstract). 



Having recently spent some time in Southern Texas and Eastern 

 Chihuahua, a country until recently overrun by the Comanches and 

 Lepans, and, hence, but imperfectly known, 1 venture to hope that a few 

 words of description of its aspects, geological structure, botany and re- 

 sources, may not be unwelcome, especially as the attention of our people 

 is being drawn in that direction, since it offers a new field for our sur- 

 plus population and for the investment of capital. 



The eastern and central portions of Texas are so well known, as to 

 require no detailed description. Near the Gulf, the climate is warm 

 and mioist, and sugar and cotton are successfully raised. Beyond this 

 belt, we pass on to plains on which there is little timber but mesquite, 

 but the surface is covered with rich grass, and it is already one of the 

 most productive grazing districts of the United States. The underlying 

 rocks are, for the most part, of the cretaceous formation, without useful 

 minerals, and the climate is dry. 



On the western side of these plains, the country is traversed by 

 mountain-chains, which belong to the Rocky Mountain system, and 

 which form the outer rim to a region, of which the topography is more 

 varied, the mineral resources greater, and the agricultural capabilities 

 less, than those of central or eastern Texas. This is, in fact, part of 

 a great table-land, that fills the interval between the eastern and 

 western mountain ranges, here nearly a thousand miles apart, and 

 which extends with diminished breadth, southward throughout the 

 central portion of Mexico. The Rio Grande has cut deeply into this 

 plateau, and, where it has forced its way through the mountains that 



