American Forestry 



VOL. XVIII 



JUNE, 1912 



No. 6 



EXTINCT VOLCANOES OF NORTHEAST NEW 



MEXICO 



BY \YILUS T. LEE 



CRAYELERS over the Santa Fe 

 route in Colorado and New 

 Mexico are probably all familiar 

 with the striking scenic features near 

 Raton Pass. Chief among these is 

 Fisher's Peak, the most conspicuous 

 object in view as one approaches Trini- 

 dad. It is an impressive mass of rock 

 that rises more than 3,500 feet above 

 the city, where the traveler stops for 

 refreshment and where the engine that 

 has raced for hours over the plain re- 

 tires and gives place to fresh ones that 

 pant and throb with impatience for 

 the long climb over the pass. This 

 peak, which by the way is not a peak 

 at all, but is the point of a flat-topped 

 table-land known as Raton Mesa, has 

 a pointed appearance when viewed 

 from below, because of the angle of 

 observation. It is the northwestern ex- 

 tremity of a volcanic region stretching 

 eastward through southern Colorado 

 and northeastern New Mexico into Ok- 

 lahoma, a distance of more than 80 

 miles. It is far removed from the 

 Rocky Mountains, its western extrem- 

 ity being nearly 50 miles from the foot- 

 hills. 



This region contains many unique 

 and attractive scenic features, but for 

 the most part these lie at considerable 

 distances from ordinary lines of trans- 

 portation, and because they are in a 

 sparsely settled and little known part 

 of the country almost nothing is known 

 of them by the general public. The 

 volcanic activity of former times is 

 evidenced in this region by the pres- 



ence of great sheets of lava, dikes, 

 plugs, intrusive sills, conical mountains 

 of igneous rock obviously of volcanic 

 origin but without depressions at their 

 summits indicative of craters, and 

 other mountains which are unques- 

 tionably volcanic but wanting in the 

 symmetry of form that usually char- 

 acterizes a volcano. 



The lava flows date back to some 

 unknown period whose antiquity it is 

 quite useless to speculate upon. Since 

 the time of the flow of which Fisher's 

 Peak constitutes a part, erosion has 

 removed from the country to the north 

 rocks about 3,500 feet thick. The mesa 

 maintains its form because of the su- 

 perior hardness of the igneous rock at 

 the top. This covering varies in thick- 

 ness from 100 feet or less to 500 or (iOO 

 feet. It was not formed by a single 

 welling out of molten rock, but by 

 many successive flows. It consists of 

 numerous sheets, probably separated by 

 long intervals of time, and were the 

 history of the lavas known it would 

 doubtless prove to be a long and va- 

 ried one, extending over centuries of 

 time ; and yet, as compared with the 

 duration of time that the volcanic 

 forces have been active here, the for- 

 mation of the lava sheet seems like a 

 single event. The surfaces of these 

 great mesa flows are more or less ir- 

 regular, and from them rise such ele- 

 vations as Red Mountain and Town- 

 drow Peak. The summit of the latter 

 rises about 450 feet above the general 



Published by permission of the Director of the U. S. Geological Survey. 



357 



