PORTLAND
BEFORE THE DAYS OF MAN
A Preliminary Article giving facts of interest relating to the
geological formations underlying the Town of Portland.
This article, while it is not history, is written as an introduction to
the History of the Town of Portland. It
should be kept as a portion of the said history.
Before entering upon a write-up of the early settlers of Portland, a
brief reference to its geological characteristics may prove of interest.
The student in search of a field for
geological study may spend many days in Portland to his advantage.
One of the oldest spots on earth is found there.
Ever since a crust was formed upon the molten mass making up the infant
earth, the Phillip Fuchs (Fox) quarry has greeted the rising sun starting on its
countless journeys across the sky. It
consists of the oldest rock in the earth's formation and is known to scientists
as quartz-porphyries or archean rock.
Its limited area is taken as proof that it was originally an island that
arose dome-like out of the surrounding sea, for at that time most of the western
continent was above water. If this
be true, the small patch of granite that constitutes this quarry has witnessed
all the climatic and geological changes that have taken place throughout the
countless centuries of the earth's existence.
It is of fire origin.
All rock and earth that rest upon the granite are in some way due to
water. The granite quarry, while a
nameless island, was surrounded by a sea that was lashed into giant waves by the
furious storm that prevailed. The
mighty work of those waves is seen in the make-up of the hill of course,
conglomerate immediately to the north of the quarry, and which is surrounded by
the highway that for a short distance parallels the Crawfish River.
Examining the exposed surface of the rock at the bottom of the ravines at
the side of the road as it approaches the river, evidence will be found that the
waves broke great boulders from ledges of granite and rolled and ground the
smaller of them into a course mortar which hardened about the larger fragments
holding them as rocks are held in a stone wall of man's construction.
This was the work of the Cambrian era in the world's history.
Above the Cambrian deposits tossed and roared the Silurian Sea whose
waters were less hostile to organic life.
It was then that the sandstone named St. Peters was formed and later
there
was
deposited upon it the Trenton limestone. Examples
of these may be seen on the north end of the Quarry, once owned by John
McCormick. Near the red barn, the
horizontal strata are exposed; the lower ones, consisting of a soft St. Peter's
sandstone of varied and beautiful colors, are overlaid with strata of the
Trenton limestone in which may be discovered the casts of the oldest settlers of
the Town of Portland. Among them are
the fossil farms of brachlopods, orthosceras, etc.
These are not numerous, which is proof of the great age of the rocks.
The earliest formed rocks carry but slight evidence of either animal or
vegetable life.
No better field for the study of glacial effects is offered than is found
in Portland. There are no
indications of the rocks formed during the immense period of time that
intervened between the formation of the Trenton limestone and the coming of the
great ice fields from the north. This
is due to the fact that the Great Silurian Sea receded after the Trenton era and
the surface of the town remained exposed until capped by the great glaciers of
the Quartenary Age.
In the meantime, the exposed
rock underwent a decomposition resulting in the formation of clays.
The surface of the town is largely marked by elongated hills that rise
abruptly on the north ends and thin out gradually towards the southwest.
The "Bluff" in the geographical center is a good illustration.
The general trend of the hills is uniformly southwest.
The surface of the granite quarry was shaven smooth by the ice passing
over it. No angular fragments of
granite are found to the northeast of the quarry, but extending to the southwest
are those that were torn from it by the moving ice and carried and strewn in
great numbers upon the surface of the marsh and mixed with the clay of the
uplands for miles and are called boulders. The
grooves or scratches made by the ice on the granite surface of the quarry extend
in the same direction with the elongated hills.
The surface of the conglomerate rock mentioned furnishes like evidence.
The upper parts of the boulders upon its surface were worn away and the
whole is planed to a perfect smoothness. All
these evidence the action of the moving fields of ice which is known in this
district to have moved to the southwest carrying and depositing fragments of
rocks, gravel, clay, etc., in a promiscuous mixture over the surface which is
now know as "drift".
In its onward course, the ice plowed
out the soft portions of the surface and was forced over rocky elevations such
as were offered by the conglomerate hill
and the granite quarry. This forward
movement of the ice, that was a thousand feet and more in thickness, and its
subsequent melting away produced the valleys, marshes and ridges that parallel
and alternate with each other throughout the township.