14 BULLETIN UNITED STATES GEOLOGICAL SURVEY. \rol.Vl. 



Spruce of the higher Eocky Mountains, is an important and good-sized 

 timber-tree. It forms the principal part of the forest in Colorado 

 between 8,500 and 11,000 feet, and at the upper tree-line is dwarfed to 

 a shrub, accompanying Pint's contorta, but growing also at higher ele- 

 vations. It is the representative of the Atlantic Spruces, in aspect and 

 in the character of the lumber resembling Black Spruce, while the cones 

 are just intermediate between those of the White Spruce and of the fol- 

 lowing. Distinct as they are on the whole in character and in station, 

 it does seem as if these ran together in a series of specimens ; while, on 

 the other hand, on its northeastern limits, between the Peace River 

 plateau and the Athabasca, east of the Eocky Mountains, iu latitude 54° 

 and 55*^, P. Engelmanni seems to pass into P. alba. This species extends 

 southward into Arizona, westward somewhat into the higher mount- 

 ains of Nevada, and northwestward into the interior plateau of British 

 Columbia. It should there be studied in its relations to P. Sitchensis of 

 the northwest coast, the original Abies MemiesH. 



Picea pnngenSj as Dr. Engelinann now calls it, the ^^ Abies Ilenziesii" 

 of Colorado, to the Eocky Mountains of which it is nearly confined, 

 belongs to an elevational range just beneath that of P. Engelmanni, 

 being sparsely associated with Pinus ponderosa^ while the latter attends 

 (and generally dominates) P. contorta., both, however, affecting moister 

 soil, as is the habit of the Spruces. The timber of the two is probably 

 not unlike. The rigid and prickly-iwinted leaves render the name of 

 P. pungens appropriate. This species takes kindly to cultivation both 

 in England and in the Northern Atlantic States. A portion of the 

 young trees display a very glaucous foliage, and are much admired. 



Abies concolor, the more southern of the two Firs of the Eocky Mount- 

 ains, accompanies Picea Engelmanni and Pinus contorta in the southern 

 part of Colorado, and extends to New Mexico, where Fendler collected 

 the specimens originally named. It passes westward in the mountains 

 of Southern Utah and Arizona, and thence extends, according to Engel- 

 mann's identification, into and through the whole length of the Sierra 

 Nevada, from 8,000 down to 3,000 or 4,000 feet of elevation, there 

 becoming a pretty large tree. Its soft wood, like that of the eastern 

 Balsam Firs, is of little account. The same is to be said of — 



Abies suhalpina, the more southern Eocky Mountain Fb, with smaller 

 cones, which most resembles the eastern A. balsamea. This, from Cen- 

 tral Colorado and from towards the upper forest limit, extends north- 

 ward to Britisli Columbia, and northeastward to beyond the mountains 

 (where it may meet and even pass into the Balsam Fir), and northwest- 

 ward perhaps almost to the Pacific coast. In the United States at least, 

 it nowhere constitutes any important portion of the forest. 



Larix occidentalis, the Western Larch, belongs only to the northern 

 part of the Eocky Mountain forest region, and to the moister portion of 

 this. Even there it seems to be an unimportant tree. 



Juniperus Virginiana, the Eed Cedar and Savin, is a tree of great 



