Wo have little idea how vast these ice-flelds
once were They covered some parts of New
England to a depth of two or three thousand
feet, completely burying Mt Tom and, per
haps, Mouadnock.
Those Now Jersey hill* which show tho lim
its of tbe ice are called a terminal moralua.
Terminal moraines mark the periods when
the 100 rested. In Wisconsin wo have
what are called kettle montlnmi. They
resemble, iu composition, tbe hills
on which Bostonia builL There is much hard
clay and scratched stones and bowldore.
In Wisconsin they are called kettles because
of their shape. Hero wo find deep depres
sions. Often they form tbe basins of lakes.
Toko, for instance, the famed lakes at Madi
son in that state. They are in reality but
great kettle holes, since filled with water.
Tho ice, which made thorn, pushed down
through Oroen Bay, while tho ice-fields of
Now England were tho roault of a movement
of icn up tho fit Lawrence rivor. As these
mighty massoa molted and eank, they did so
very uuevonly. In sumo places slight depres
sions were made, which went on increasing in
size, sinking over deeper and dooper. Then
tho incited ice-wator came rushing and pour
ing into these until it filled them, when, over
flowing, it cut ita way oceanward.
Often great walla of solid ice reared their
grotesque and mighty forms all about them.
As the traveler in polar regions seei thorn to
day, the lake region of Minnesota is a series
of these kettlo-hnles. The mass of ice over
this region and northward was from two
thousand to eight thousand foot in dopth.
