Show exploration IN YUKON KOYUKUK REGION ALASKA that part of central alaska lying between the lower koyukuk river and tile the yukon was until recently but little known in 1913 it was explored by H al eakin and his results are presented in a report entitled the yukon koyukuk region recently issued by tile the united states geological survey as bulletin the region is essentially a rolling upland above which rise some higher mountain masses reaching altitudes of to feet this upland is broken by broad valleys and lowlands the mountain slopes are clothed with spruce trees up to altitudes of 2000 feet spruce and birch also cover the lowlands above timber line the vegetation is chiefly moss tile the timbered areas notably in the lowlands are broken by meadows covered with a luxuriant growth of grass moose caribou and bear still roam over much of this region which is seldom visited by white men no important mineral resources have been found in the yukon koyukuk region but many of the stream gravels carry some fine colors of gold this gold seems to have been derived from the contact zones of gigantic intrusive rocks which are abundant in tile the region that some of these deposits are of commercial importance is shown by the fact that the placers of the indian river district which lie in the yukon koyukuk region have for several years been mined on a small scale it is not improbable that other commercial placers may be found in the region but the prospecting thus far done does not indicate the presence of any very rich deposits |