8 Raymond John Pool 
were very oppressive with high temperatures and low humidities. 
The winters are cold and the summers hot for the region as a 
whole. The following table shows the mean annual precipitation 
for a number of stations within the range of these studies: 
Bott Garland: recente nace 35.70 cm. (14.00 in.) 
Sarit Lilie iis win tease ec abate 29.50 cm. (11.62 in.) 
PGA GO! di Ne mont nares os en eee ae 46.00 cm. (16.16 in.) 
VERTICES so Aisi ciacecnate eeahrrare Le coos 48.80 cm. (17.29 in.) 
Montrose (caste kis inetd aime tasers 30.80 cm. (12.30 in.) 
Buenas Waste Coates eee 22:20-cm\( *B75cate) 
CUMIN OI os tyes eee nee era 2310 em,. CG, 50 10H) 
Preblow acu.ueih sash tonics see 30.70 cm, (12.11 in.) 
Colotado -Springsys Acai. ce heck: 2 36.80 cm. (14.41 in.) 
Bou eR vite we aie site was eee 47.00 cm. (18.75 in.) 
Hot Sulphur: Springs? <5). ois: 50.80 cm. (20.00 in.) 
Moraine Packs sc cce ck come see 38.20 cm. (15.00 in.) 
STRUCTURAL STUDIES 
Artemisia tridentata. 
Since this is the plant which gives character to the formation 
it will be treated more thoroughly than the others, most of which 
are herbaceous species. This is the common plant of the West 
which predominates in those regions commonly called sage plains, 
or sage-brush regions. The species is a perennial shrub and is 
variously called by the names sage-brush, common sage-brush, 
sage-wood, mountain sage, etc. The short stem is usually much 
branched at or near the ground into from three to six or more 
slightly spreading or erect secondary stems. The main stem 
reaches a diameter of 15.20 cm. (6 in.) in the south. The tallest 
plants found were at Fort Garland, where they measured 2.50 m. 
(8 ft.) in height, and the smallest were in Estes Park, where the 
general height was about 45.60 cm. (18.0 in.). The species 
reaches considerably larger dimensions farther north and west 
where the formation is older. The main stem is often split and 
furrowed in nature and is covered by a thin, stringy, dark brown 
to ash-colored bark. The young twigs are silvery canescent. 
A18& 
