Tom and Pat Leeson 
down-folding of the area lying between 
the two ranges formed the Puget 
Sound Trough. During this critical pe- 
riod the subtle divergence of the 
Olympic ecosystem began. 
Little is known about the evolution 
of mountain goats or the history of 
their dispersal, but it would appear 
that the events that isolated the Olym- 
pic Mountains had already taken place 
when the animals colonized the North 
American continent. Paleontologists 
have suggested that ancestral goats 
evolved in Asia and entered North 
America over the Bering land bridge 
that existed at various times in the 
geologic past. The skeletal remains of 
Pleistocene mountain goats, including 
those of a smaller, extinct species 
( Oreamnos haringtoni), have been 
found in eight separate localities rang- 
ing from the Yukon Territory to Mex- 
ico. The oldest-known remains come 
from British Columbia and date from 
the Sangamon Interglacial period, 
some 140,000 years ago. 
Because of their isolation, the Olym- 
pic Mountains were not easily acces- 
sible to mountain goats or other Old 
World colonizers. The long-term iso- 
lation of the region is reflected in the 
presence and often abundance in the 
Cascades of at least seven other 
mammals that are not found in the 
Olympics. These include the pika, a 
small relative of the rabbits and hares; 
the Cascades red fox; and the Cas- 
cades golden-mantled ground squirrel. 
Geographical isolation has also re- 
sulted in the evolution of animals that 
are endemic, or unique, to the Olym- 
pic Mountains. Not surprisingly, these 
are alpine species, since the alpine 
areas of the peninsula are effectively 
islands in a lowland sea. Prominent 
among these endemics is the Olympic 
marmot, a large colonially living ro- 
dent. Perhaps less noticeable, but no 
less unique, are twelve species and 
varieties of endemic alpine plants. 
Species unique to the Olympic Moun- 
tains include Cotton’s milkvetch, Pip- 
er’s bellflower, Flett violet, Flett flea- 
bane, Webster’s senecio, and rock 
spirea. The remainder are geographi- 
cally distinct varieties of species that 
are also found in the Cascades, such 
as the mountain wallflower ( Erysi- 
mum arenicola var. arenicola ) and the 
Olympic rockcress ( Arabis furcata 
var. olympica). 
There is growing concern about the 
future of the delicately flowered al- 
pine plants, particularly since their 
range overlaps that of the introduced 
'om and Pat Leeson 
Left: Two goats rest atop Hurricane 
Hill during the heat of a summer 
afternoon. Such ridges afford the 
goats a view of possible predators 
approaching from below, while 
cooling breezes help them to regulate 
their body temperature. Above: 
Roughly three days old, a kid trails 
its mother while she feeds on a 
precipitous slope. Kids are highly 
precocious and can walk a few hours 
after birth. The nanny is shedding 
her coat of hair, as all mountain 
goats begin to do in late spring. 
Isolated from other mountain 
ranges, the Olympic high country is 
surrounded by the waters of the Pa- 
cific Ocean, the Strait of Juan de 
Fuca, and Puget Sound, and by the 
lowlands of the Chehalis River Valley. 
Geologic evidence suggests that be- 
tween twelve and twenty million years 
ago a shifting of the earth’s crust cre- 
ated a mountain range running east 
to west across what is now the state 
of Washington. During this transfor- 
mation, the regions to the north and 
south of the present Olympic Range 
were depressed, forming the Strait of 
Juan de Fuca and the Chehalis River 
Valley. A second event that occurred 
about five million years ago completed 
the isolation. At this time, the Olym- 
pics were elevated further, the Cas- 
cades were formed, and a concurrent 
61 
