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Thus, then, with the very first emergence of dry land out of the heavily saturated and steaming mineral waters of the primeval ocean, we have Pilot Knob, Shepherd Mountain, and a few smaller peaks in their vicinity, forming an island in the vast expanse. The next nearest island was a similar one at the Black Hills, in Dakota. There is no reason as yet known for believing that any form of life, either animal or vegetable, had yet appeared in our Missouri region. The ocean water was still too hot, and still too powerfully surcharged with mineral salts, alkalis and acids to admit of any living tissues being formed; and the atmosphere was in like manner thickly loaded with deadliest acids in the form of vapors, which would partially condense as they arose, and fall upon the ironheaded islands to form a mineral crust, and then be broken and washed back into the sea. But this process being kept up and incessantly repeated for millions of years (see Prof. Helmholtz's estimate at bottom of the chart), both sea and air became gradually purified of its excess of minerals and acids; and the water sufficiently cooled to admit of living tissues being formed; and meanwhile the condensing and crust-forming elements precipitated from the vapor-laden air or deposited directly from the bulk waters of the shoreless sea, were busily forming the solid earth. The different incrustations would each be a little different in their component elements; and then being broken up and mixed together and recombined, partly in the form of rough fragments, partly in the form of dust or sand ground into this state by mechanical attrition, partly in the form of fluidized or vaporized solutions, and partly in the form of molten masses produced directly by the earth's internal fires, the process of combining and recombining, with continual variation in the proportions, went on through the long, dreary, sunless and lifeless Azoic Age.

But as soon as the great ocean caldron got cooled down to about 200 degrees Fahrenheit, it was then possible for a very low form of vegetation to exist; and although no fossil remains of the first existing forms of such vegetation have yet been found, or at least not conclusively identified as such, yet graphite or plumbago, the material from which our lead pencils are made, is found in connection with the transition rocks between the Azoic and the Zoolithian ages. Graphite is not a mineral at all, but is pure vegetable carbon, and is supposed to be the remnant carbon of these first and lowest forms of tough, leathery, flowerless sea-weeds. Some small deposits of graphite are reported to have been found in connection with the iron and metamorphic granites of our Pilot Knob island; and that would indicate the first organic forms that came into existence within the boundaries of what now we call the state of Missouri. Just think of it! All North America, except a dozen widely scattered spots or islands, was covered with an ocean that spread its seamy expanse all around the globe; no sunlight could penetrate the thick, dense cloud of vapors that filled the enveloping atmosphere; according to our English author before cited, this was 600,000,000 years ago, a period which the human mind cannot grasp; but the Almighty Maker of worlds had even then commenced to make the state of Missouri and its living occupants.

The earliest known forms of animal life, a kind of coral-making rhizopod (root-footed) called Eozoon Canadense, are not found in Missouri, but are found abundantly in what are called the Laurentian rocks, in Canada and elsewhere. (See chart). It is not to be supposed, however, that the enormous period called the " Age of Zooliths " passed, with forms of animal life existing in Canada, but none in our iron island region, unless we assume that the mineral acidity of the waters coming in contact with this island was so intense as to require all that vast period for its purification sufficiently to permit the existence of the lowest and most structureless forms of protoplasmic matter known to science. Prof. Swallow says, in writing on the Physical Geography of Missouri, "below the magnesian limestone series we have a series of metamorphosed slates, which are doubtless older than the known fossiliferons strata; whether they belong to the Azoic, the Laurentian or Huronian, I am unable to say."

The labors of our different state geologists have not discovered any fossil remains in Missouri lower down in the rock scale than what is called the "Lower Silurian" formations, which form the first half of the "Age of Invertebrates " in the zoic-calendar portion of Prof. Reid's chart. The term "Invertebrates " includes all forms of animal life that do not have a back-bone, such as polyps, mollusks, worms, insects, crustaceans, infusoria, etc. By the time this age (Silurian) had commenced, our lone island had been joined by large areas northward, southwestward, eastward and northwestward, so that there began to be a continent: and several hundred species of animals and plants have been found fossil in the rocks of this period, but they are all marine species—none yet inhabiting the dry land. Our chart shows the Lower Silurian epoch sub-divided into Cambrian, Canadian and Trenton formations; but there are other local sub-divisions belonging to this period, the same as to all the other general periods named on the chart. The animals of this period were polyps or coral-makers; worms, mollusks, trilobites,asterias (star-fishes), all of strange forms and now extinct. The trilobite, some species of which are found in Missouri, was the first animal on the earth which had eyes, although there were likewise a great many eyeless species of them; but the fact that any of them had eyes during this age is considered by some scientists to prove that the atmosphere had by this time become sufficiently rarefied to let the sunlight penetrate clearly through it and strike the earth. On the other hand, others hold that this did not occur until after the atmosphere had laid down its surcharge of carbonic acid and other gases, in the forms of limestone from animal life and coalbeds from vegetable life; that is, there was nothing which we would now consider as clear sunshine until the carboniferous period. At any rate, Prof. Dana says of the Lower Silurian, "there was no green herbage over the exposed hills; and no sounds were in the air save those of lifeless nature,—the moving waters, the tempest and the earthquake." Having thus given the reader some idea of the beginnings of land and the beginnings of life in our old, old state, space will not permit us to linger with details upon the remaining geological periods. We have compiled the following table from various writings of our able state geologist, Prof. G. C. Swallow, of the State University:

ROCK FORMATIONS OF MISSOURI.

Igneous Rocks.—Granite, porphyry, syenite, greenstone, combined with those wonderful beds of iron and copper which are found in the Pilot Knob region.

Azoic Rocks.—Silicious and other slates, containing no remains of organic life, though apparently of sedimentary and not of igneous origin.

Lower Silurian— Feet thick.

Hudson river group (8 local subdivisions) 220

Trenton limestone 360

Black-river and birds-eye limestone 75

1st magnesian limestone 200

Saccharoidal (sugar-like) sandstone 125

2d magnesian limestone 230

2d sandstone 115

3d magnesian limestone 350

3d sandstone 60

4th magnesian limestone 300

Total thickness of Silurian rocks 2035

When the reader remembers that these were all formed successively by the slow process of the settling of sediment in water, he will get some idea of how it is that geology gives such astounding measurements of time.

Upper Silurian— Feet thick.

Lower Helderberg formation 350

Niagara group 200

Cape Girardeau limestone 60

Total thickness 610

Devonian

!Chouteau limestone 85 Vermicular sandstone and shales 75 Lithographic limestone 125

Hamilton group 40

Onondaga limestone (extremely variable). Oriskany sandstone (doubtful). Carboniferous

Coal measures, consisting of strata of sandstones, limestones, shales, clays, marls, brown iron ores and coal 2,000

In this formation there are from eight to ten good workable veins of coal; and the Missouri basin coal-bearing area is the largest in the world. It comprises the following:

Square miles.

In Missouri 27,000

Nebraska 10,000

Kansas 12,000

Iowa 20,000

Illinois 30,000

Total 99,000

The Sub-Carboniferous in Missouri is subdivided into:

Feet.

Upper Archimedes limestone 200

Ferruginous (irony) sandstone 195

Middle Archimedes limestone 50

St. Louis limestone 250

Oolitic limestone 25

Lower Archimedes limestone 350

Encrinital limestone 500

Total sub-carboniferous 1570

Cretaceous.—The Triassic and Jurassic formationshave not been found in this state; but Prof. Swallow has classed as probably belonging to the Cretaceous epoch, six different formations which comprise a total thickness of 158 feet. He says no fossils have been found to certainly identify these beds, but their geological horizon and lithological characters determine their place in the scale.

Tertiary.—The beautiful variegated sands and clays and shales and iron ores, which skirt the swamps of southeast Missouri along the bluffs from Commerce to the Chalk Bluffs in Arkansas, belong to this system.

Quaternary.—In this Prof. Swallow includes whatis separated under the name of "Recent" by Prof. Dana and others, as shown in the chart. The Quaternary of Missouri is subdivided by Prof. Swallow into—

Alluvium 30 feet

Bottom Prairie 35"

Bluff {Loess of other authors) 200"

Drift (altered drift, boulder beds, boulder clay) 155"

Total Quaternary formations. 420"

That brings the succession of geological formations consecutively from' their beginning up to the present time: and now our own eyes behold every day the processes of nature going on very much the same as they have gone along through all the unthinkable lapse of time that has passed since Pilot Knob first pushed its brazen brow up above the strange desolation of waters when "darkness was upon the face of the deep." And now our next consideration must be, the present aspects of the land surface of our state, together with its streams, its woodlands and its wonderful mineral wealth and resources.

MINERAL RESOURCES.

In the extent, variety, and practical value of her stores of mineral wealth, Missouri is not excelled by any other state in the Union. In the fall of 1880 the New York Economist published an article on Missouri, in which it said:

"The state of Missouri is one of the most remarkable pieces of this earth's surface. Surface indeed! Missouri goes far enough under the surface to furnish mankind with one hundred million tons of coal a year for thirteen hundred years. Think of 26,887 square miles of coal beds—nearly half the state—and some of the beds nearly fifteen feet thick. With regard to iron, it is not necessary to penetrate the surface for that. They have iron in Missouri by the mountain. Pilot Knob, 581 feet high, and containing 360 acres, is a mass of iron; and Iron Mountain, about six miles distant from it, is 228 feet high, covers 500 acres, and is estimated in the last surveys, to contain 230,000,000 tons of ore, without counting the inexhaustible supply that may reasonably be supposed to exist below the level. There is enough iron lying about loose in Missouri for a double track of railroad across the continent.

"The lead districts of Missouri include more than 6,000 square miles, and at least five hundred points where it can be profitably worked. In fifteen counties there is copper in rich abundance. There are large deposits of zinc in the state. There is gold, also, which does not yet attract much attention, because of the dazzling stores of this precious metal farther west. In short, within one hundred miles of St. Louis the following metals and minerals are found in quantities that will repay working: gold, iron, lead, zinc, copper, tin, silver, platina, nickel, emery, coal, limestone, granite, marble, pipe-clay, fire-clay, metallic paints, and salt."

It can hardly be said that gold, silver, tin, platina or emery have been

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