90 YEARBOOK, PUBLIC MUSEUM, MILWAUKEE [Vol. II. 



found, as the climate there is far too arid to permit the growth of trees. 

 However, as the plateau is ascended, one comes upon a zone of small 

 juniper and pifion trees, and, at an altitude of six thousand two hundred 

 feet, reaches a fine growth of yellow pine. This continues upward to 

 about eight thousand live hundred feet above the sea where the yellow 

 pine gives place to other trees such as fir, spruce and aspen, which clothe 

 the higher mountains to a height of fully twelve thousand feet. This 

 forest growth is due entirely to the increased rainfall, caused by the high 

 altitude, the clouds tending to accumulate about the peaks in this region, 

 so concentrating the rainfall on the slopes of the mountains. 



The mountains themselves are all volcanic, and belong to that group 

 of cones known as the San Francisco Volcanic Field. Most of the 

 cones are composed of loose piles of volcanic cinders or pumice, and 

 range from one hundred to a thousand feet in height above the gen- 

 eral level of the desert. The outflow of lava from these various vents 

 covers an area about fifteen miles wide, from north to south, and sev- 

 enty miles long, from east to west, culminating in San Francisco Moun- 

 tain with an altitude of twelve thousand six hundred and eleven feet. 



There are several hundred cinder cones in this field and they present 

 a great variety in size, height and state of preservation. The one to 

 which we first directed our attention was unnamed on the official maps, 

 but is called locally "Cave Hill." It consists of a loose pile of cinders 

 and ash roughly semi-circular at the top, due to the fact that one side 

 of the crater had been blown out. 



The loose cinders forming the slope of this cone were in many places 

 intercepted by rough masses of lava, which formed a more or less solid 

 rock mass. In this lava were numerous caves and openings into the 

 hill and it was found that many of these, if not all, had at one time been 

 inhabited by the Indians living in this region. These people had left 

 behind them many traces of their habitation, such as broken bits of pot- 

 tery, fire-blackened layers of soil, etc. Such evidences of a former oc- 

 cupation are said to be present in many of the different cinder cones of 

 this volcanic area. 



A more detailed description of these cave dwellings is given else- 

 where in these pages.-) 



We attempted to reach a very interesting pueblo ruin, situated some 

 distance from Flagstaff, on the edge of the Painted Desert. On our 

 way we again passed through the Coconino forest, which in this section 

 resembles a park rather than a primeval forest. There is very little 



«A Trip to Cave Hill, Arizona, pp. 176-182. 



