100 PROCEEDINGS OF WASHINGTON MEETING. 



nitude, from which a narrow stream of lava flows southeastward about 20 miles. 



There are other areas in western New Mexico of volcanic lava, notably that south 

 of Grand station, on the Atlantic and Pacific railway. 



In Trans-Pecos Texas no craters have been noted, although they may occur in 

 the mountainous regions. Many old volcanic pipes or necks without lava flows 

 occur between Austin and Del Rio, but they are of entirely different type and age 

 from those of New Mexico. The relation of those cinder cones and sub-recent tl< >ws 

 to those of northwestern New Mexico and Arizona cannot be stated from personal 

 observation. 



Proceeding southwest ward into Mexico they still continue, and in cases exhibit 

 evidences of activity, increasing southward toward the neck of Mexico where the 

 present epoch seems to represent but a southern continuation of the volcanic and 

 lacustral conditions which so recently prevailed over the northern portion of the 

 basin region. 



The fact that these cinder cones and lava flows occur in the floor of the Quater- 

 nary lake basins is indicative of their recent origin. It is possible that future 

 investigations will show an intimate connection between the drying up of the 

 basins and the activity of these volcanoes. 



It is also evident from the investigations that eruptive activity has occurred in 

 the Texas-New Mexican region from Cretaceous to the present time, and at least 

 three well-defined epochs are at present recognizable which mayserve as a guide 

 to future observations, viz : 



fragile structure like the .New .Mexican cinder cones is the most convincing evi- 

 dence of newness 



The foregoing features are presented without any attempt at broad correllation 

 with the coastal or other regions of the United States, although they present a 

 tempting field therefor. For the present, however, 1 prefer to leave this task to 

 others, hoping that the remarkable Tertiary and Pleistocene history will receive 

 that attention which it deserve-. 



