Daily globe. [volume] (St. Paul, Minn.) 1878-1884, 1883-01-26
GEOLOGICAL FORMATION.
A Free Lecture by Prof. Edward Daniels.

A Free Lecture by Prof. Edward Daniels.
The Academy of Natural Scisnce is en-
joying course of free geological lectures.
The second lecture was delivered yes
terday by Prof. Edward Daniels, of Wis
consin.
The lecturer described the two great
classes of rocks which make up the crust
Of the globe as stratifed and unstratifed.
The former are arranged in layers, the lat
ter are irregular and massive. The strait
fed rocks were formed by the washing
down of former rocks and the deposit of
their material in the ocean. Similar de-
posts are forming now from mud washed
down by the streams and carried out to sea.
The coarse materials drop near the mouths
of the great rivers and form deltas. The
fine matter is distributed by waves, tides
and currents and forms with each spring
flood thin film over the
whole floor of the ocean. Each
year the same thing occurs and the
result is, annual layers build up into great
fer nations in the thousands of centuries.
The various forms of ocean and land life
are buried in the mass, and petrifes as it
consoIidates by pressure OF the waters and
chemical processes. These rocks are thus
sure to be successive deposits and are
therefore arranged in layers, each of which
represents a portion Of time. They may
be considered as successive volumes by one
author, each finished and laid down in the
very order of its composition. Together
they form record of the experiences of
our planet for millions of years before
man. The rocks seen and underlying this
beautiful city belong to this class. A
vast ocean once rolled its waters here
Astounding in monad life. The remarkably
regular layers so like masonry, seen in ex-
cavations in this city, is the same rock
found at Trenton falls, New York, contain
ing the same strange forms of life which
crowd the layers of this rock all over the
Mississippi valley.
The unstratiied rocks were once fixed
masses like the lavas of our active yolca-
noes. They are hence also called igneous
rocks Granite, which is a composite rock
consisting of quartz, feldspar and mica,
is the type of this class. The region north
of US, around Lake Superior, abounds in
ain masses in the Penokie range, and
| rising like islands in the vast expanse of
the stratifed series. They indicate the
points where former volcanoes poured out
their fiery floods or the primitive rocks
| cooled from their original incandescence.
These rocks are forming now in. the
fiery floods of active volcanoes cooled
in contact with the o. into light
| porous Stag, or under water into solid
! compact forms. Modern lavas are
as various in form as the ancient rocks of
this class. Some are as coarse as furnace
Stag, and others like the celebrated Petit
Lois, Mount Kelawen, in the Sandwich
Islands, fbrons and soft as silk.
Two great agencies are constantly at work
modifying the land surface of the globe.
one tending to work it down, lowering the
highest points, filling the valleys and d.
minishing the land masses above the sea
level. This is the effect of water fltering
upon the surface, penetrating into the tex
ture of rocks, dissolving the cements or
freezing and bursting these apart by me-
chanical force. The particles thus sepa-
rated are borne downward by storms to
the lower levels. Great valleys and gorges
are thus cut out. The valley of the Colo
RADIO, the Mississippi, the great gorge be-
low the falls of Niagara were thus cut out.
The mounds, of Wisconsin, the turrets like
Castle rock, the Garden of the Gods, in
Colorado, and the wonderfully picturesque
buttes of the Bad Lands are remnants or
| outlines of vast formations thus swept
away. This process also determined the
present forms of all the great mountain
masses of the world. The principle val
legs also had this origin. This process is
known by the terms erosion, denudation
and weathering of the rocks.
It depends upon the movement of the
| waters and the atmospheric changes
| Heat, light, electricity and chemical agen-
cies are ever active in promoting these
changes. These constitute the mightiest
agencies of waste and destruction, though
often silent and unobserved in their action
Volcanic forces tend to increase the
amount of land above the watsr. The con-
tinents have been lifted above the sea by
successive efforts of the subterranean
forces. The mountains have not been
raised to their lofty attitudes by sudden
throes. Silent and persistent elevations are
going on now all along the coast lines.
| At Nova Scotia, along the coast of Scandi-
navia, and elsewhere, the incest observa-
lions are being made, and the throes are
found to be steadily rising. In earth
quakes, sudden elevations of few feet are
common. At times subsidences also oc-
cur. The rocks record frequent successive
| elevations and su5sidences in past ages, as
seen in the wonderful petriied
| forests of the Yellowstone Park,
and in the coal seams,
one above another, each representing a
surface covered with richest vegetation,
carried down beneath the ocean. Three
pillars of the Temple of Jupiter Scraps
now stand near the sea coast in Italy.
They are bored with perforations of a
shell fish that dissolves hmestones, and
| inserts it's shell to height OF twenty feet.
The shells still remain in the holes. The
evidence is conclusive that the surface
upon which this temple stood, has sunk
and remained for many years under the
level of the sea, and remained there till
its pillars became the dwelling of col
ony of she'll fish. Then it arose SO gently
| that the pillars still hold their vertical pc
| sition.