Layer By Layer, The Ground-Up
Masses Were Deposited In The Inner Ocean Bed, Parts Of Which Were Now
Practically Shut Off From The Vast Ocean Beyond.
How many centuries of
centuries this process continued geologists do not tell us.
Time is so
vast, so long, that they cannot divide those early days into weeks, months
and years, as we now do.
The Continent is born. After many millions of tons had been thus ground up
and tossed about and mingled with the waters of the seas, the earth, in a
fit of fiery anger, turned and baked them, with intense heat, out of all
semblance to their former appearance. These baked masses, in the course of
time, were thrust up out of the seas, mashed and macerated once more, again
deposited as sand, silt, pebbles and boulders, and again burned. These
processes followed each other, how many times we do not know, the earth all
the while keeping up her steady uplift of the children of her bosom out of
the great sea. Higher and higher came the land. Further and further receded
the sea, until, in due course, the sun shone upon a vast area of land that
was the rude skeleton of what is now the continent of North America.
It would have taken a keen eye, however, to have imagined from that which
we see to-day what was there. The Gulf of California reached far up, even
into Nevada, and covered what are now the Mohave and Colorado Deserts;
there was no California Coast Range; the Gulf of Mexico was vastly larger
than it is to-day, covering all Florida, and reaching up the Mississippi
Valley half-way to the Great Lakes.
The First Strata. It was just preceding the last uplift of this epoch that
the era of deposition of rock debris was so prolonged that twelve thousand
feet of strata were washed into the bed of the sea, in the region now known
as the Grand Canyon Country. It was at the time when life was beginning to
dawn, for in the remnants of the strata are found fossils of the earliest
known life. These strata, therefore, are of immense interest to the
geologist, as they are the first known rocks containing life to emerge from
the primeval sea. Within the last few years, they have been called the
Algonkian Series, and later I shall speak of them more freely.
Prior to the deposition of these Algonkian strata, the Laurentian rocks
(the granite) upon which they rest were subject to a long period of
"planation," - as the grinding down and leveling of rock surfaces is termed.
After this planation was complete, a subsidence occurred; the whole area
became the bed of an inland sea, and upon the planed-down granite, the
debris that formed the Algonkian strata was washed.
While they were being deposited, the whole region was the scene of several
seismic and volcanic disturbances, for great dykes and "chimneys" of lava
are found, showing clearly that, by some means or other, the strata were
broken and shattered, cracked and seamed, and that through these cracks the
molten lava oozed - forced up from the interior of the earth.
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