116 GEOLOGY. 
along the line of the Upper Mississippi, and the Great Lakes, and 
the St. Lawrence. 
The next period, the Age of Fishes, was characterized by tran- 
quil seas filled with coral reefs, around which sported the primeval 
fishes. Huge Nautili spread their sails over the placid waters, and 
plants clothed the rising continent in green. At the close of this 
age the Pacific retired a little to the northwest and left a narrow 
belt of Devonian rocks along its sinuous shores. These are colored 
green on the map. 
For many cycles the seas remained tranquil and continued to be 
filled with numerous fishes, corals, stone lillies, trilobites, star fish 
and algz, while the vast beds of Carboniferous limestone were 
deposited. But toward the close of this period turbulent times 
intervened. Rocks were broken up, rounded to boulders and peb- 
bles, or ground to sand, and drifted to the sea and piled into vast 
beds, in the central portions of the Mississippi Valley. 
St. Louis now rose above the waters and formed a peninsula 
which had its connection to the South with the older part of the 
continent. A shallow bay extended around St. Louis to the North 
and West. It widened out over all the coal regions of Illinois and 
Kentucky and opened out into the Pacific through St. Charles. All 
Northwest Missouri, and the coal regions of lowa, Nebraska, Kan- 
sas, Arkansas and the Indian Territory were covered with warm 
shallow waters, steaming under the rays of tropical suns. 
A hot atmosphere filled with vapor and carbonic acid nourished 
the rapid growth of trees, ferns and sigillaria, and other plants in 
vast forests. Steaming marshes, fens and lagoons abounded. The 
lands were many times raised and submerged, and the forests swept 
away into vast beds, which formed the coal deposits over more than 
100,000 square miles in the States above named. ‘The turbulent 
waters deposited the : clays and sands intercallated with the coal 
beds Clear tranquil waters returned filled with fishes, mollusks 
and corals, and the limestones of the coal-measures were deposited. 
Such changes followed each other in some twenty successive 
courses, revolving through the vast cycles of the Age of Plants. 
At the close of this period the Pacific had retired westward to 
Sioux City and Manhattan; and the Gulf of Mexico extended up 
as high as Cape Girardeau, and a part of Scott County was a large 
island. 
During the succeeding Age of Reptiles, while the vast saurians, 
like the Zeuglodon, were sporting in the waters that covered the 
Lower Mississippi Valley, and the flying Pterodactyli were flapping 
their wings over the shores of the Pacific, in Wyoming and Colorado, 
Missouri was quiescent, producing her quota of animal and veget- 
able life. 
In the succeeding Age of Mamma/s Missouri remained as before, 
but the regions bordering on the Gulf of Mexico and those on the 
Upper Missouri and westward to the Pacific, underwent various de- 
pressions and elevations by which several dynasties of wonderful ani- 
mals were buried in the rocks which now contain their remains. At 
the close of this vast period the continent assumed its present form, 
with some unimportant exceptions. The Gulf of Mexico still 
extended above the mouth of the Ohio. Our large rivers had cut 
their present channels to depths varying from 100 to 300 feet, and 
in width from 1 to 10 miles. Mighty waters poured over the solid 
strata and wore for themselves these vast channels to the sea. 
But a change came over the continent. Some mighty power of 
water or ice, or both, swept over the surface, grinding the softer 
rocks to atoms and rounding the harder into pebbles, vast boulders 
were moved hundreds of miles and dropped in strange places. 
Another change, and a large part of the Upper Mississippi and 
the Lower Missouri Valleys were covered with a vast fresh water 
lake. ‘The land was covered with forests similar to our own. The 
land and waters were peopled with many of our present races of 
animals. The beaver built his dams as now. ‘The squirrel ate the 
same mast and the deer cropped the same herbage. But the huge 
elephant and mastodon were then lords of the soil. The Bug 
formation was deposited in this lake. Another change and the 
lake was gradually drained and the waters subsided to the channels 
of the rivers. The currents of the great rivers were sluggish, their 
waters were spread from bluff to bluff, and the Bottom Prairie was 
deposited. 
Again the level changed, the great rivers became more rapid, 
and cut their present channels in the Bottom Prairie. 
The alluvial deposits were formed, the gulf was driven back to 
its present limits, the swamp country was added to our State, the 
soil was formed, and Missouri was finished. 
The Age of Man commenced, and the Geological Record gives 
place to History. 
DEVELOPMENT AND NATURAL SELECTION. 
But in this countless array of animals, whose orders and genera 
and species have come and gone through the vast cycles since Pilot 
Knob announced the rising continent, among them all, do we 
find one species of animal developed from another? JVay, verily. 
Species come without progenitors, maintain their identity for 
countless ages, and utterly perish, leaving nothing developed to 
call them ancestors.. : 
But have not the species, and genera, and orders, improved by 
natural selection? Not at all. 
When we examine through their whole existence, they degene- 
rate rather than improve. In some instances they do improve for 
a time; but in almost all instances they retrograde again, and 
finally perish miserably. 
The Trilobite was one of the first animals that appeared in the 
primeval ocean; he lived through the entire palzozoic period. 
They sometimes improved and sometimes degenerated ; but finally 
they dwindled down to a few insignificant species, and utterly 
perished, — 
The Trilobite stood at the head of the primitive orders. He 
had the world for his field and all time was before him. He 
perished by no catastrophe; and yet natural selection did not 
improve him, and much less save him from utter extinction. 
At the close of the Age of Mammats, the elephant and masto- 
don were at the head of the order on this continent. They had 
space enough, climates enough, time enough, and none to molest 
or make them afraid, and yet natural selection could not save them. 
They dwindled away and died out. 
The genus Cyrtia and the species Spirifer cameratus, and a thou- 
sand others might be named to show that natural selection, where 
it had the widest field, the longest time, and the most favorable 
circumstances, failed utterly to make a new species. 
