Geology of Peoria County. , 15 
ical affinity of their constituents, each aided probably by a cementing process 
from mineral or metalic solutions. But the time, the heat, and the pressure, 
were doubtless most potential, in accomplishing these results. 
Of these rocks, we find some of almost pure quartz, or feldspar, or mica, or 
other elementary substances; others are a mixture of crystalline fragments as 
in the granites, of quartz, feldspar and mica, or the syenites, in which horn- 
blend takes the place of mica, or the diorites which are composed mostly of 
feldspar and hornblend. 
But while these modes of-rock formation were in progress, another of a very 
different character was taking place. Jimestone in large quantities is found, 
in these first made — the Laurentian beds. How did it get there? It was not 
formed like the rocks just described. It is the product of the animal king- 
dom; its source from animal life. 
For a long time no evidence had been discovered that life existed during 
the formation of these strata, except the limestone itself. But at last the 
little architect of these vast limestone ledges was found,— the Hozoin Cana- 
dense,— meaning the dawn of life. 
The shelly coverings of this minute animal,— was the source of the material 
from which the limestone was formed. They belong to the lowest order of 
animal life. Are classed with the Foraminifera of the group Protozoa. We 
are well acquainted with them, and their work, for they are as active to-day, 
as at that time, right under our observation. Their life-work is apparent, and 
doubtless has been during all the ages. 
Large areas of the bottom of the North Atlantic are covered with their 
remains to a depth we have no means of determining. It is called Globerge- 
rina ooze. Under the microscope they are seen to be of many forms and sizes, 
and of beautiful colors. 
It is remarkable, that the few specimens found, should have been preserved 
through all the changes, to tell their story. Changes resulting from the great 
heat which metamorphosed these stones, and the “forces which have broken, 
_and folded, and crumpled, the Laurentian beds in a most remarkable manner.”’ 
Thus was formed the Archaen system, which includes both the Laurentian 
and Huronian beds. And in like manner were deposited and formed all the» 
rocks of succeeding time. The higher strata, however, were formed from the 
detritus of the secondary rocks; and a great portion of the limestones were 
from the remains of larger and higher orders, of which the radiates became a 
very important factor. These two beds were piled up, until they attained a 
thickness in Canada of 40,000 to 50,000 feet. Seven to nine miles in height! 
How long did it take to accomplish this vast work? Any estimate of the 
time must be more or lesgconjectural, but if we make one year a unit in the 
life of aman, we must take one million years as a unit in the life of the 
earth’s growth. 
One scientist, Sir Wm. Hamilton, I think, estimates that seventy millions 
of years must have elapsed from the first Laurentian deposits until the pres- 
ent time. Croll makes it one hundred million. 
The whole globe was covered with water during the time of the formation 
of these beds, except a narrow strip of land, shaped like a bended arm, the 
elbow resting on Lake Superior and extending to the Northwest to the arctics, 
and Northeast to Labrador, together with a few small islands, some of which 
were the nuclei of subsequent mountain ranges. 
It was in the /ower Laurentian that the beginnings of life were found. The 
first was doubtless that of vegetable life; although we find thus far, no records 
of any individual plants in their original forms, yet, the resultants of such 
life are found, in the graphites so considerably distributed throughout the ~ 
beds. It is also quite certain that animal life could not have existed without 
this necessary food —‘‘a vegetable pabulum floating in the water.” 
