History of Saginaw county, Michigan; together with ... portraits ... and biographies ... History of Michigan ...

CHAPTER VII.

SCIENTIFIC.
GEOLOGICAL.
The geological formations of the Lower Peninsula vary little
from those of New York, Western Canada and Wisconsin. The
first, the oldest formation, exists in the Upper Peninsula. Its rocks
point out to the geologist the fact of its antiquity, and enable him
to conclude that, if it is not actually the nucleus of this continent,
it is at least coeval with the first formations. It has been stated
that the land reaching from Trenton Falls to Saratoga was the first
that appeared above the sea on the creation. Here are the trilobites in great variety, all modeled in black marble, so perfectly
preserved in form that the multitudinous lenses of their, eyes are
as apparent under the microscope as are those of a living fly.
Millions of years before man walked the earth these creatures lived
their life; the limestone took on their forms; they had become everlasting stone millions of years before there was a living man to see
them. Of late years, however, the opinions of many men are in
favor of locating the first upland north of Lake Huron, extending
through Southwestern Canada to New York State. This is known
as the Laurentian system, and is characterized by granite, gneiss
and Syenite rocks. It existed long years before the dlrainage of
the great sea, and was old even at the beginning of the Silurian
era. Approaching nearer to the Valley of the Saginaw is the Huron
system-something bearing the same relation to geology that the
"Iron Age" does to history, from the fact that its mean characteristics are iron ores, quartz, chlorites, and all the rocks peculiar to
the northern iron mines. Age may not be said to have aided in
the formation of these ores; nor is it within the scope of the geological knowledge of the present time to decide definitely as to the
period or manner of their formation.
There are numerous systems and groups of rock connected
with the Upper Peninsula, and with the northern portion of the
Lower, entirely unknown in Central and Southern Micligan. It
is stated by Winchell, Rorninger, Hall, and some of their reviewers, that the "group of rocks wlich form the Lower Peninsula of
Michigan, being like so many oblong saucers one within the other,
depressed in the center of the State and outcropping at the edges,
comprise, first, or lowest, the dolomitic limestones which are regarded as the Ielderberg group of New York. These are the
oldest strata, whose outcroppings are found in the Lower Peninsula,
and the lower portions are regarded as the bottomi of some lagoon
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