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PART II.-PHYSICAL AND INDUSTRIAL.

GEOLOGY AND MINERALS.

The geological history of Missouri commences at the very bottom of the scale, or, in what may be termed the fire-crust period of geologic time. (See chart on page 67). Dana's "Manual of Geology" is the great standard work all over the United States on this subject. In his chapter on Archæan Time he gives a map and brief sketch of our North American continent as it existed at that remote period, which was, according to a calculation made for the Royal Society of London in 1879,* about 600,000,000 years ago. And as this is where Missouri first comes to light, we quote Prof. Dana's account of the very meagre areas and points of our continent which stood alone above the primeval ocean that then enveloped the entire globe with its bubbling, seething, sputtering wavelets-an enormous caldron of boiling, steaming silicious lye, rather than water. Dana says:

"The principal of the areas is The Great Northern, nucleal to the continent, lying mostly in British America, and having the shape of the letter V, one arm reaching northeastward to Labrador, and the other northwestward from Lake Superior to the Arctic. The region appears to have been for the most part out of water ever since the Archæan era.† To this area properly belong the Adirondack area, covering the larger part of northern New York, and a Michigan area south of Lake Superior, each of which was probably an island in the continental sea before the Silurian age began.

"Beside this nucleal area, there are border-mountain lines of Archæan rocks: a long Appalachian line, including the Highland Ridge of Dutchess county, New York, and New Jersey, and the Blue Ridge of Pennsylvania and Virginia; a long Rocky Mountain series, embracing the Wind River mountains, the Laramie range and other summit ridges of the Rocky Mountains. In addition, in the eastern border region, there is an Atlantic coast range, consisting of areas in New Foundland, Nova Scotia and eastern New England. In the western border region, a Pacific coast range in Mexico; and several more or less isolated areas in the Mississippi basin, west of the Mississippi, as in MISSOURI, Arkansas, Texas, and the Black Hills of Dakota."-Dana's Manual, p. 150.

*See Popular Science Monthly, May, 1879, p. 137.

The "Archæan era," as used by Prof. Dana, in 1874, (the date of his latest revision) included both the "Azoic Age," and "Age of Zooliths," as shown on the chart, p. 67. When Prof. Dana wrote, it was still an open question whether the "eozoon" was of animal or mineral origin; but the highest authorities are now agreed that it was animal; and Prof. Reid has, therefore, very properly given it a distinct place in his "Zoic Calendar."

GEOLOGICAL CHART;

Compiled

Including the Rock Scale of Geological Periods and the "Zoic Calendar of Creation." from the works of Agassiz, Lyell, Huxley, Hæckel, Dana, LeConte, and other first rank authorities in Science at the present time. By HIRAM A. REID, Secretary State Academy of Sciences at Des Moines, Iowa. [Published by permission of the Author.]

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EXPLANATION.-The side line at the left shows what portions of geological time are comprehended In the terms "eozoic," "paleozoic," etc. The first column shows the periods or "Ages" of geological time during which the different successive types of animai life predominated, or were the highest types then in existence. And these two divisions form the "Zoic Calendar of Creation."

The second column shows the great general groupings of rock strata,in which are found the fossil remains of the corresponding animal types named in the first column. But, at the "Age of Reptiles" occurs a grand divergement, for it was during this age that animal life pushed out into its most wonderful developments; and there came into existence strange f and marvelous forms of swimming reptiles, four-footed and two-footed walking reptiles, and two-footed and four-footed flying reptiles. Here also the true birds began to appear, though with reptilian peculiarities; and likewise the marsupial animals, which are a transitional type, between reptiles that produce their young by laying eggs and the true mammals, that bring forth their young well matured and then suckle them. The third column shows the lesser groupings of rock beds as clas-A sified by our American geologists; 4 but many minor subdivisions and local groups are omitted for want H of space. At the top of this column are shown the geological periods of first appearance of races 0 of man, so far as now authenticated by competent scientific au- H thorities.* 0 N

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"The existence of Pliocene man in Tuscany is, then, in my opinion, an acquired scientific fact."-- See Appletons' International Scientific Series, Vol. XXVII, p. 151. "The Miocene man of La Beauce already know the use of fire, and worked flint."- Ib. p. 243. See also, Prof. Winchell's "Pre-Adamites," pp. 426-7-8. "The human race in America is shown to be at least of as ancient a date as that of the European Pliocene."-Prof. J. D. Whitney. Similar views are held by Profs. Leidy, Marsh, Cope, Morse, Wyman, and other scientists of highest repute.

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.

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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 fossiliferous 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.

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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.

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