144 KANSAS ACADEMY OP SCIENCE. 



others not so high get good supplies. Breadth of ranges seems to 

 figure a good deal in the rainfall. 



New Mexico is dotted and overspread with later intrusions than 

 her granitic wrinkles, and of a different character. Basaltic cones 

 and lava-beds intermingle in all parts of the territory, west of the Llano 

 Estacado, with her mountain ranges and her park-like plateaus. 

 Rhyolite often caps the summits of the higher peaks; but they were 

 not the higher peaks when the molten rock was spread over them. 

 Subsequent erosion has left them to tower above the crumbling 

 granite masses by which they are surrounded, and which once looked 

 down upon the sites now occupied by the cold vomit of Pluto. 

 Young isolated cones of basalt rival in altitude the porphyritic mon- 

 archs of many geological ages. A line of these in a southwest direc- 

 tion begins near Colorado, between the Sangre de Cristo range and 

 the Bio Grande river, and extends 200 miles. Among these peaks, 

 Ute, San Antonio, Abiquiu, Hemas and Mt. Taylor are between 

 10,000 and 12,000 feet high. Mt. Capulin, in the northeast quarter 

 of the territory, a noted landmark, 8000 feet high, has a crater a mile 

 in diameter. Ten miles west of Albuquerque are five cinder cones, 

 from 6000 to 8000 feet above sea, in a line, and visible from the city. 

 The central one has an open crater and a secondary cone. Some of 

 the basalts are vesicular or amygdaloid, and some massive and dark- 

 purple basalt weathers to a white kaolin. Some rhyolites are pumi- 

 ceous and some glassy and massive. Of course there are other 

 varieties. The lava overflows are extensively spread on the plains or 

 parks. A region of lava overflow, 300 miles in length and averaging 

 twenty miles in width, in the midst of which the plutonic peaks 

 above named and many others lift their heads above the desolation 

 they have wrought, runs through northwestern New Mexico. In its 

 northern part it is basaltic, and lies on both sides of the Rio Grande, 

 which cuts through it in long, black chasms, in places 800 feet deep. It 

 leaves the eastern side of the river about the parallel of Santa Fe, but, 

 on the western side, is still a visible object from the city of Albu- 

 querque, presenting the appearance of a perpendicular, high, black 

 wall. A bed of black obsidian covers about 300 square miles a little 

 southeast of the territorial center. It is known as the Malpais. 

 Many sheets with local names might be mentioned in other sections 

 of the territory. 



As might be inferred, dikes and sills are numerous, and have ef- 

 fected important economic conditions, among which is the conversion 

 of bituminous coal into anthracite, and the introduction of some 

 metallic ores of profitable mining value. It is, however, a question 

 whether the extrusive and intrusive plutonics have made New Mexico 

 more fitted than it would otherwise have been for the production of 



