ECOLOGICAL NOTES FROM NORTH-CENTRAL 
COLORADO 
By FRANcIS RAMALEY AND W. W. RoBBINS 
The following three studies were made by the writers in June 1907 
while on a collecting trip in northern Larimer County, Colorado. All 
the work was recorded in the field notebooks. The office work has 
consisted in putting the material into form for publication. 
Vegetation Studies at Red Mountain.—Red Mountain! is in Larimer 
County, Colo., about 26 miles by road northwest of Ft. Collins. It isa 
butte formed by the erosion of wide valleys all around it. The material 
of the mountain is sedimentary rock, chiefly rather fine-grained sand- 
stone. The strata are nearly horizontal and the harder and softer 
layers, weathering at different rates, mark off a series of ledges at dif- 
ferent heights. The top of the mountain has an altitude of 7,095 feet 
and extends about 600 feet above the surrounding country. Cerco- 
carpus bushes (Cercocarpus parvifolius) are distributed about evenly 
all over the top and sides of the mountain but these thin out and stop 
rather abruptly at the base where the inclination of slope is more gradual 
and where there is an accumulation of soil.2 On the north side of the 
mountain only there are some scattered pines (Pinus scopulorum) and 
cedars (Sabina scopulorum) but these are all very far apart. 
A typical place on the south side of the mountain was selected for 
study and an area two meters square sloping gently to the south was 
staked off and mapped. The map, which is here reproduced, shows the 
location of Cercocarpus bushes and indicates their distance apart. In 
addition to these shrubs there are various herbaceous plants as indicated. 
Immediately at the south base of Red Mountain is a considerable 
area, about 500 meters wide sloping down to Ten Mile Creek, the soil 
of which is a fine-grained sand. Here there is a valley grassland for- 
1 For a map of this region see an article entitled ‘‘Botany of Northeastern Larimer County, Colo.,” by 
RAMALEY in these Studies, Vol. V, pp. 119-131. 
2 See in this connection the account of the Cercocarpus Scrub Formation in the article named above. 
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