SOME GEOLOGIC ASPECTS OF CONSERVATION 
149 
the eastern margin of the Wisconsin drift it is developed as far 
south as Hardin county, while on the western front it is con- 
spicuous south to Carroll. An inner moraine, formed during the 
recession of the glacier, reaches intermittently in a broad loop 
from Winnebago county south into Boone and Greene and north 
again through Palo Alto and Emmet counties. While it differs 
markedly from the Driftless Area of northeastern Iowa this 
morainic area has many features of great charm. Its great 
mounds, many of them bare and gravelly, but some timber cov- 
ered on their slopes or summits, the depressions among the hills, 
with an occasional lakelet nestling calmly in quiet beauty, all of 
these make an assemblage which can not fail to impress him who 
has eyes to see and a soul to appreciate Nature’s handiwork. One 
of these great mounds, Ocheyedan Mound, in Osceola county, has 
long enjoyed the reputation of being the highest point in Iowa 
and while apparently it must yield precedence, at all events it 
is a landmark which is visible for miles around. Pilot Knob, in 
northern Hancock county, while not rising so high above the sea, 
rises twice as high above the plains about it as does Ocheyedan 
mound, and with its associated lakelet and timber groves is one 
of the charms of central Iowa. 
The beautiful lakes of northcentral Iowa form another group 
of geologic features which are intimately associated both in dis- 
tribution and in origin with these moraines, and which comprise 
one of the most attractive and valued types of Iowa’s localities 
cf natural interest. Everyone is drawn by the quiet beauty of 
a smooth-lying sheet of water set like a glistening diamond 
amidst low grassy shores or steeper wooded bluffs. And so it 
is that our lake regions appeal to all of us and we think of them 
and their popularity with justifiable pride. 
A lake is one of the most evanescent and transient of natural 
phenomena. A stream may expand and increase its tributary 
area until it grows into a river : a mountain may, for a long time 
at least, keep pace in its growth with its decay : but the destiny 
of a lake, and especially of a glacial lake; is as inevitable and as 
'easily foretold as the destiny of a man. And in comparison with 
the vast stretch of geologic time it is as short lived. For this 
reason it is all the more imperative that we do all in our power 
to conserve what lakes we have, to lengthen their lives so far 
as in us lies, to preserve for the coming generations these gems 
of beauty in our fields of emerald. 
