24 



SCIENCE 



[N. S. Vol. XXVI. No. 653 



their height, the lower portion of each sud- 

 denly contracted, shortened and turned for- 

 ward, and lacking much of reaching the base 

 of the shaft. Bases of all the teeth indis- 

 tinguishably fused into a shaft which was 

 probably more or less curved. Median longi- 

 tudinal channel at the base of the shaft prob- 

 ably, but not certainly, present. 



DIMENSIONS OF L. FEERIEBI 



Mm. 



Greatest extent of the crown of hinder tooth . . 44 

 Greatest anteroposterior breadth of same crown 17 



Thickness of base of same crown 13 



The figure of the specimen is two thirds 

 the natural size. ' Oliver P. Hay 



COON MOUNTAIN CRATER 



Considerable interest has been manifested 

 during the past year or two concerning the 

 origin of a remarkable crater-like depression 

 located on the summit of a slight elevation 

 known as Coon Mountain or Coon Butte. It 

 may be found on the plateau region of north- 

 ern Arizona, but slightly removed from a 

 locality of recent extreme volcanic activity 

 where over a hundred volcanic cones may be 

 seen, many of which still possess well-defined 

 craters. Interest in this phenomenon has been 

 revived as the result of the adoption and 

 elaboration on the part of a few writers of the 

 local common talk of the inhabitants of the 

 immediate neighborhood of the mountain. 

 Here it is religiously believed that an im- 

 mense meteor nearly one half mile in diameter 

 buried itself in the earth, forming a deep 

 cavity with an upturned edge or rim very 

 much as when a bullet is allowed to fall into 

 soft mud. Some of the reasons cited for this 

 belief are : (1) The circular shape of the de- 

 pression, (2) the large amount of meteoric 

 iron fragments' (over ten tons) which has 

 been collected in the immediate vicinity, and, 

 (3) the entire absence of all kinds of vol- 

 canic ejectamenta, or even heated or meta- 

 morphosed material, within the area covered 

 by a radius of several miles. 



During the summer of 1906 the writer, 

 while studying the crater cones and lava flows 

 of the San Prancisco Mountain district, in- 



^ Known as the Canon Diablo meteorites. 



cidcntally made a visit to this interesting 

 locality and this report is the result of the 

 impressions received at that time. 



An admirable description of the elevation 

 has recently been presented to the public 

 through the publications of D. M. Barringer 

 and B. C. Tilghman,^ as well as the results of 

 the investigations which they made by means 

 of shafts and borings in the bottom of the 

 crater in search of the great meteorite. It is 

 sufiicient here to call attention to only a few 

 of the most important facts. The crater is 

 about 3,500 feet in diameter and nearly 600 

 feet deep. The elevation on which it is 

 located is about 150 feet above the surround- 

 ing planes and from a distance presents the 

 appearance of a narrow circular wall with a 

 very jagged summit. The rocks in the im- 

 mediate vicinity and also forming the walls 

 of the crater, are made up of layers of sand- 

 stone of greatly varying composition. The 

 cementing material is calcareous matter 

 which in some places is present in sufficient 

 quantities to classify the rock as a silicious 

 limestone. The whole formation is known as 

 the Aubrey limestone (and sandstone). 



The strata is upturned, forming the rim of 

 the crater exactly as one would expect if it 

 had been lifted by some force from below. 

 It has been frequently faulted and displace- 

 ments of a few feet can readily be seen in 

 several places on the walls of the crater. The 

 most remarkable feature to be observed, how- 

 ever, is the complete absence of any evidence 

 of vulcanism. No lava is found and not the 

 slightest metamorphism of any kind has taken 

 place in the sediments. Further, there is no 

 evidence of solfataric action, or changes of 

 any kind except mechanical erosion, having 

 taken place after the cavity was formed. 

 The nearest lava fields are located nearly 

 fifteen miles distant. These are in the 

 vicinity of San Francisco mountain and are 

 associated with a remarkable crater cone 

 known as Sunset Peak, an elevation made up 

 of fine ash, lapilli, and lava blocks. In the 

 lava blocks are frequently found masses of 



' " Coon Mountain and its Crater," by D. M. Bar- 

 ringer, and " Coon Butte, Arizona," by B. C. Tilgh- 

 man, Proc. Acad. Nat. 8c. of Phil., December, 1905. 



