The true northerner. [volume] (Paw Paw, Mich.) 1855-1920, 1877-11-23
B,Yp.G,OSE AGES.

Prof. Denton recently delivered in st.
Paul lecture upon the very interesting
subject above announced, the following
report of which we copy from the Pho
neer. Press: He began with reference
to what he termed the matchmaking
process of nature" such as the washing
of sand and clay beds by the rains, and
their consequent functions in filling up
some lake or hollow in the oceans bed.
Successive layers are thus deposited ON
some muddy shore, forming beds of clay
which will harden into shale, of which a
large portion of the earth's crust is COM
posed. af --v asga. r nls,s Ia
The Mississippi river has evidently
cut its way back from Lake Pepin, as It
is now eating away the rock at the Falls
of st. Anthony. 1t has quarried out
billions of tons of sandstone and
limestone, which its waters have ground
to powder and swept down to the gulf.
from which portion of it comes back
in the shape of cotton, rice and sugar.
Prof. Denton then reverted to the gods
of the Chinese and Scandinavians, who
were represented as builders or workers,
bringing form and order out of chaos;
and how many there are still ignorant OF
the fact that the sand and limestone cliffs
of the Northwest were formed mt the
bottom of an ocean that once covered
the territory millions of years before
man became an inhabitant of our plan
ct. BY examining these rocks we find
the kind of beings that inhabited our
planet before continents were born and
the mountains brought forth. The
earths crust reveals the order in which
its various rocks were deposited. Re-
cent deposits include those in which the
remains of man are found. The ter
tiary beds reveal fossil mammals, many
of them now extinct. The Irish elk and
the mastodon probably survived the ear
beds represent time when rep
tiles and reptilian birds existed, and
when corals, fishes, ETC., were distinct
from living forms. The Oolitic and Lii
assic times were the ages of sea and land
saurians diving, crawling,
or even flying. The professor followed
with reference to other ages of the
world, as revealed by geology, when
only oceanic and insignificant forms ex-
listed, or wholly untenanted. save by the
humblest forms which the heated oceans
contained. There was still older time,
no doubt, when no water was found,
and the earth's surface consisted OF
dark, rough rocks, formed by the cool
ing of the fiery material that once rolled
in waves over it. After this came a time
when water condensed upon the surface,
and shallow ocean was everywhere.
As the earth cooled, the contraction OF
its crust ridged it up into craggy hills,
and from these streams rolled down
sand and pebbles into the heated ocean
beneath-too hot, probably, for the ex-
istence of any but the simplest forms OF
life. Then the continent of North Amer
lea began to emerge from the waters-a
range of hills stretching to the northeast
and northwest from the ST. Lawrence
river and the lakes. A range of islands
marked the range of the Rocky noun
tains and the Appalachian chain. From
these islands" streams rolled sand and
pebbles to the ocean, forming the Lau-
rentian and Huronian rocks, and other
deposits found in different portions OF
northern portions of it, III places to q
depth of over 30, 900 feet.
1t is probable that life in simple forms
existed during this time. but the rocks
have been 80 altered by heat that nearly
all traces of it have been destroyed or
obliterated. After the Laurentian and
Huronian periods came the Silurian-
the lowest rocks deposited during that
time, and consisting of the Pottsdaa
sandstone, or the lower sandstone of the
Northwest, so called to distinguish it
from the st. Peters sandstone, which
may be seen down the Mississippi river
from Minneapolis to Fort Smelling.
This deposit is eighty feet deep at Potts
dam, N. Y, and on the st. Croix more
than 500 feet. In the Northwest it con-
sists of minute grains of quartz with
little cementing matter, hence it easily
crumbles, and great masses of it are
worn away, as by the river at Lake Pc
pln-forming the land upon which Lake
City stands and the lowland farms in its
vicinity. Where these grams are &C.
mented, the rock has a browner color,
as at Eau Claire, where some of its beds
have stood for ages. The places of de-
posit in different sections were mentioned
representing large but shallow ocean
overspreading the American CONT
nent, having land lying to the north and
northwest, on which must have been
mountain ranges of quartz, from
which rivers washed the pebbles and
ocks and ground them to powder,
and carrying this to the sea, forming the
| Pottsdam sandstone. Whatever doubt
may exist about the occurrence Of fossils
in the Laurentian rocks, there is none
about their existence in the Pottsdam.
The ocean that then covered Minnesota
and most Of North Amenca swarmed
with life in variety of forms, of which
the rocks bear abundant evidence. This
"life" was illustrated and described in
8 very interesting manner, and the diff
ferent creatures in the stages of develop
ment, and the action of storms and other
commissions upon the surface of the
earth were graphically portrayed, but
ut such length that even summary is
impracticable. Then came the grand
winter of the ages. Over this whole
country an icy sheet lay, moving south
ward at the rate of few inches per day
from north to south, it ground down the
rocks in its march; it brought down the
| bowlders that are scattered over your