1 [ BULLETIN IMTKD STATES GEOLOGICAL SURVEY. \Yol.VI. 



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

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

 between 8,600 and 11,000 feet, and at the upper tree-line is dwarfed to 

 a shrub, accompanying Pinus 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 

 .ire 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 docs seem as if these ran together in a series of specimens; while, on 

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

 plateau and the Athabasca, east of the Bocky Mountains, in 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. tfitchensis of 

 the northwest coast, the original Abies Menziesii. 



Picea pungens, as Dr. Engelmann now calls it, the u Abies MenziesiV 

 of Colorado, to the Rocky 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. eontorta, 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-pointed leaves render the name of 

 /'. 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 Rocky Mount- 

 ains, accompanies Picea Engelmaimi and Pinus contorta in the southern 

 part of Colorado, and extends to £Tew Mexico, where Fencller 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 t<> :i,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 subalpina, the more southern Rocky Mountain Fir, with smaller 

 cones, which most resembles the eastern ,1. balsam ea. This, from Cen- 

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

 ward t<> British Columbia, and northeastward t<> beyond the mountains 

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

 ward perhaps almost to the Pacific coast [n the United States at least, 



it now hero constitutes any important portion of the forest. 



Laria occidentalism the Western Larch, belongs only to the northers 

 pari of the Bocky Mountain forest region, and to the moister portion of 



This. Eveil their it seems to be an unimportant tree. 



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



