SALMON INVESTIGATIONS IN IDAHO IN 1895. 
155 
In discussing the fauna and llora of central Idaho, Dr. Merriain gives an excellent 
account of the forests of this region. ‘ He assigns the Sawtooth Mountains and their 
adjacent and contained valleys to the following life zones: 
1. Arctic-Alpine zone, from the upper limit of tree growth or timber line to the tops of the highest 
peaks. The height of the timber line varies according to slope exposure from 10,000 to 11,000 feet. 
2. Subalpine or Timber-line zone, occnjiying the strip from the upper limit of stunted tree 
growth down to the upper limit of full-grown, perfect trees. The dwarfed trees growing in this zone 
are Abies subaJpinus, Pinus albicauUs and Picea engelmaniii, and the limits of the zone lie approximately 
between 10,000 and 11,000 feet. 
3. Hndsonian or Sitruce zone, lying between 9,000 and 10,000 feet. Its characteristic trees are 
the same as those of the Suhalpiue zone, hut in this they obtain full and perfect size. 
4. Canadian or Douglas fir zone, lying between 7,700 and 9,000 feet. The characteristic trees are 
the Douglas hr ( Pseudotsitga douglasii) and the Murray pine ( Pinus tnurrai/ana), with a few of Picea alba 
and Popidus tremul aides. 
5. Neutral or Transition zone, occupying the strii> between 6,400 and 7,500 feet altitude, and with 
the sage-brush ( Artemisia irideniaia) as its most characteristic plant. 
That portion of southern Idaho having an elevation of less than 6,400 feet and 
comprising the great Snake Eiver plains, he assigns to his Upper Sonoran zone. 
The forests about the Eedilsh lakes are composed almost entirely of the coniferous 
species already mentioned. In the immediate vicinity of the lakes is the Murray iiine 
and occasional examiiles of Douglas lir and white spruce, though these two species are 
most abundant on the slopes some distance above the lakes. A few small, white- 
bark pines were seen near Altnras and Pettit lakes, but this species reaehes its 
maximum size and abundance in the Hndsonian or upper timber zone, as stated by Dr. 
Merriam. 
This region has never been mapped, even with approximate correctness. The 
United States Geological Survey is now engaged in making a topographical survey 
of this portion of Idaho. Through the kindness of Mr. Henry Gannett, chief topo- 
grapher of the Survey, and Mr. E. T. Perkins, jr., topographer in charge of the Idaho 
field work, the Commission has been imrmitted to use the plane-table sheet of the 
Sawtooth region, and the accompanying map is based upon the Survey’s work. That 
portion of the map north of Yellowbelly Lake is approximately correet only as to 
general features, as that region has not yet been examined by the Survey. Our own 
observations did not extend nortli of ATellowbelly Lake except in Salmon Eiver Valley 
and in the immediate vicinity of Eedfish Lake. 
The following pages give detailed descriptions of the different lakes which we 
examined. 
ALTURAS LAKE. 
This lake, which is sometimes called Sawtootli Lake, is situated about a mile^ 
northwest from the village of Sawtooth, from wliich it is separated by a densely 
wooded morainic ridge which rises some 600 feet above the lake. The greatest width 
of the lake is about four-fifths of a mile, and its greatest length about 2 miles. The 
general direction of its longer diameter is nearly northeast and southwest. The shore 
line is quite regular, there being no considerable bays or coves. Throughout the 
up])er li miles of the lake the oiiposite shores are approximately iiarallel and, as 
already stated, about four-fifths of a mile apart. 
'North American Fauna, No. 5. The elevations given l)y Dr. Merriam, referred to liere, are all 
somewhat too great. 
^The distance by trail over the ridge is about 3 miles. 
