Untitled

52 THE EXPLOKATION OF THE CAUCASUS
taken into account. I have noticed that the crystalline schists are
generally bare, while the granites and limestones are clothed in
forests. The slates of the southern chain are heavily wooded on
the south side, but bare in the Ardon basin.
The deficiencies as well as the excellencies of the Caucasus must
be noted. It possesses no remarkable waterfalls, no lakes, and
few tarns — neither sub-mountainous lakes like Como, Garda,
Geneva, Lucerne, nor clusters of tarns lik(^ tbose that dot certain
crystalline districts of the Alps.' WaterfeUs worth a special visit
are not very comniori even in Switzerland. I would not attach
to their absence more weight than it may reasonably bear. An
inference might be drawn in fa\-our of the Caucasus having been
more waterwashed, of the torrents having had force and time to
cut themselves a way out of their difficulties. Geologists may
possibly find other reasons in the disposition or dip of the strata.
The absence of lakes is a more serious matter, and must be
faced by those who believe that the great prehistoric glaciers
meet it in one of
excavated lake-basins. They will they
probably
either assert that
'
the Caucasus never
two ways :
may
had a glacial epoch,' or that 'its glaciers excavated basins which
have been either tapped or silted up by subsequent water
action.' The evidence will, no doubt, be made fuller, but already
sufficient facts have l)een collected by Abich and Favre to show
that the glaciers of the Caucasus at one time reached to the
northern plains. Erratic blocks have been found near and be-
yond Vladikavkaz. We are entitled, therefore, to dismiss the
first supposition. On the other hand, an existing basin may be
emptied of liquid in two ways, either by tapping it or by
filling it with solid. It is argual)le that lake-basins may have
existed in the Caucasus and been subsequently obliterated by
either pi-ocess. A recent traveller in the Sierra Nevada of
North America, Mr. Muir, has described very clearly the process
of lake - destruction bv these methods he witnessed afoincr on
'
According to Dr. Ricliter (In hack Eegioiun : Berlin, 1895)
lakes or tarns in the Alps east of the Splugen.
tliere are no less than 2460