THE LIVING WORLD. 
TREE PORCUPINE (Cercoiabes prehensilis). 
and some persons suppose that oral tradition still survives, relating to their ex¬ 
istence in that country. Their bones are found, in some districts, in the accu¬ 
mulation of peat in the fens, and on marshy river borders. Until recently they 
were abundant in the Northern, Middle and Western States of the United States, 
as the large number of their dams, 
and of the beautiful level beaver- 
meadows, caused by the accumula¬ 
tion of soil and filling up of their 
ponds by alluvial matter, suffi¬ 
ciently indicate. The gradual 
clearing up and cultivation of the 
country has, however, banished them, 
mile after mile and day after day, 
from the haunts of intrusive and 
encroaching man, until the beaver 
is scarcely to be found at all on 
this side of the streams which have 
their springs among the roots of 
the Rocky Mountains. Even there, 
also such unwearied war do the 
wild trappers of the various fur com¬ 
panies wage against them, and so 
largely tempting have been the 
sums paid for their spoils, that they are rapidly decreasing, and may ere long 
become extinct. It has been said, however, that the application of silk to the 
manufacture of hats, and the large use made in late years of plain felt, by 
causing a very material fall in the price of beaver has procured them such a 
respite, that they are again 
becoming numerous in 
places where they were a 
few years since almost ex¬ 
tinct. 
The beaver colonizes 
like the ancient Greeks 
and the modern Europeans. 
The old move up stream 
where living is more plen¬ 
tiful, and the young gp 
down stream, but the origi¬ 
nal home always retains 
tenants. When it builds 
an island lodge, it makes 
one straight, ascending 
pathway, and a second sinuous and abruptly descending. The bank lodges 
have already been described. The California beaver makes no dams: the 
Missouri beaver constructs slides on the banks. When building dams the 
beaver walks, on its hind legs and carries the stone pressed against its breast. 
When the wood is at any distance it builds canals twenty-five feet in width 
and three in depth and “ rafts its lumber.” 
32 
