79 
In treating the coniferous forests formations of the southern 
or Park Mountain Region, Professor Harshberger mentions the 
following belts: (1) Pinus ponderosa belt, (2) Pinus monticola 
belt, (3) Abies subalpina belt. These three “ belts" were evidently 
taken from Leiberg's Survey of the Coeur d'Alene Mountains. 
As stated before, this region belongs to the northern Rockies and 
fits poorly with the Park Region of Colorado. The low-land 
Pinus ponderosa, which gave the name to the first belt, is not 
found in Colorado. It is there represented by the up-land Pinus 
scopulorum, often regarded as a variety of P. ponderosa. Pinus 
monticola is lacking altogether. Regarding the Abies subalpina 
belt it may be remarked that Harshberger makes the following 
statement: “The Abies subalpina belt exists above 5,000 feet.” 
This is true as far as the Coeur d’Alene region is concerned, but 
does it give a correct impression, when the Park Mountains of 
Colorado are considered? I doubt if it occurs here below 9,000 
feet, and it does not form a belt, but grows scattered. In Colo- 
rado, Picea Engelmannii, not Abies subalpina, is the characteristic 
tree of the Subalpine zone. The three belts given above char- 
acterize better the Selkirks of the Dominion District than the 
Park Mountain District of southern Wyoming, Colorado, and 
northern New Mexico. Harshberger gives practically nothing 
definite concerning the zonal distribution of the trees of the 
latter district. The zones here are four and rather distinct. 
(1) The foot-hills or transition zone: between the plains and 
the mountains proper. This could well be called the juniper 
or cedar belt. North of the Arkansas Divide, the characteristic 
woody plant is Juniperus or Sabina scopulorum, mixed with Pinus 
scopulorum, Cercocarpus montanus, Rhus trilobata and its relatives, 
etc. South of the Arkansas Divide the characteristic trees are 
Juniperus or Sabina monosperma and Pinus edulis. Above these 
is usually a belt of chaparrel consisting of scrub-oaks, service 
berries and skunk-brush. (2) The montane zone or pine belt, 
with Pinus scopulorum, P. Murrayana, P. flexilis, Pseudotsuga 
mucronata, Abies concolor, Picea pungens, etc., rather mixed. 
(3) The subalpine zone or spruce-aspen belt. On the 
northern cooler slopes Picea Engelmannii is predominant, but 
