588 
POPULAR SCIENCE REVIEW. 
be got by wells sunk a few yards into tbe rock at tbe bottom. 
Beyond these vast plains to the soutb_, we come to another kind 
of country. Lofty mountain chains rise abruptly and gi’andl}^ 
from the plains. Deep ravines and long lines of valley run 
up far into the mountain sides^ narrow grooves conduct the 
traveller between elevated peaks_, and a region is entered where 
there is only a partial^ broken^ and elevated plain or plateau^ 
whose surface is irregular_, but in a very different sense from 
that of the low plains to the north. This mountain country 
is altogether distinct in its character. Its depressions are 
different in form ; its features are picturesque ; its drainage is 
distinct ; the rainfall upon it is generally greater_, and owing 
to the form of the ground_, the rain runs off from it rapidly. 
Such are the conditions of the country in which the lake basins 
occur Avkose history is one of the chief objects of discussion 
at the present time among geologists. 
It must not be supposed that such lakes are confined to 
the great central east and west elevation^ of which the Alps 
is a leading feature. The old mountain chain ranging north 
and south from Scandinavia^ through the western countries of 
Europe^ encloses a country in wliich mountain lakes also occur. 
Such are some of those of ISTorway and the deep fjords or inlets 
of its western coast. Such are the lakes and friths of Scotland 
and England. All exhibit the same general character • 
all exist in a country where the surface has been exposed not 
only to the running of water, but where the passage of ice 
either as glacier or iceberg has been traced by independent 
evidence, and within a very late geological period. 
In North America again there is a vast tract of compara- 
tively low land east of the Bocky Mountains, and north of the 
fortieth parallel of latitude, which resembles geographically the 
great plains of Europe, but is so different in climate as to offer 
few points of physical resemblance. Here the lakes that occupy 
the depressions are enormously larger, equally numerous, and 
more characteristic. Here are the vast waters of the Lakes 
Superior, Michigan, Huron, Erie, and Ontario all communi- 
cating with one another, and all ultimately communicating* 
wdth the sea by the St. Lawrence. But these are true lakes. 
The plain is to a great extent a plateau or lofty plain, and the 
form of the lakes approximates them to that of the European 
lakes. New Zealand again (see plate) repeats their forms 
among groups of mountains very clearly marked and con- 
taining abundant ice, and among the loftiest of the Andes is a 
lake at an elevation of nearly 13,000 feet, whose magnitude 
in that position renders it almost an anomaly among the 
lakes of the world. (See the form of Lake Titicaca in the 
plate.) 
