VOLCANIC PHENOMENA OF COON BUTTE REGION, ARIZONA. 



BY CKARLES R. KEYES. 



(Abstract.) 



It will be recalled that Coon Butte is a low eminence, with a shallow 

 depression in the summit about half a mile across, that has become 

 widely known on account of the supposition that this crater-like basin 

 was formed by a huge meteor striking the earth at this point and throw- 

 ing up the low wall all around. Contrary to the recently expressed 

 views regarding the origin of this remarkable crater the most critical 

 evidences seem to indicate that this feature of the local landscape is only 

 one of the many manifestations of the explosive type of vulcanism so 

 I)revalent throughout this region. 



There are in Arizona and New Mexico myriads of volcanic cones. 

 Many of them are symmetrical cinder-cones ; some are low lava-cones ; 

 some are cinder-cones with breached crater rims from which basalt-flows 

 extend for distances of several miles, some are the centers from which 

 the country about has been flooded with lava. A number of these vol- 

 canic vents display abundant evidences of dry explosive action. To one 

 of these special attention is called for the reason that it is similar in 

 every respect to the Coon Butte, except that from the bottom of the 

 crater there rises two small ash-cones about 300 feet in height. This 

 locality is locally known as the Crater Salt lake ; and is in the western 

 part of Socorro county, in New jMexico. The floor of the crater is flat 

 and is now occupied by a shallow saline lake, whence the name. 



The important feature of the Crater Salt lake is that there is displayed 

 a stage in its formation which is entirely wanting in the case of Coon 

 Butte. Conclusive testimony is here furnished that the craters in the 

 plains are the result of the explosive action of local vulcanism. If they 

 were located anywhere else but in an arid region the craters would be 

 filled with water, as in the cases of the crater lakes of Italy. Coon Butte 

 and Crater Salt lake represent the initial stages of volcano-building, 

 and a stage rarely exposed to observation. 



The apparently unusual abundance of meteoritic materials for which 

 the Coon Butte region has been so long famous is not an exceptional 



