148 FARMERS' INSTITUTES. 



some of which were 100 feet Ions:, darted swiftly through the sea by means of 

 powerful oar-like tails, — sea rei)tiles — roamed fearlessly over the land, for they 

 were the monarchs of the time — land mammals— or flew, by means of huge bat- 

 like wings, through forests and over the land — flyiug re})tiles. The few birds 

 of the time had long, bony tails and toothed jaws, and were at most as much 

 like reptiles as like birds. Man and the other higher mammals were wholly 

 absent. The third time includes to-day and showed a higher style of life. 

 While this time shows many of the simpler forms of life which were present 

 in the older times more or less modified, it is very different in the extent and 

 variety of the highest types of life, both animal and vegetable. We call it the 

 recent time or "Age of Mammals." This term is very appropriate, as the mam- 

 mals are the highest animals, and at this time were very numerous and varied. 

 All these facts, as will be inferred from what has already beeu stated, have been 

 gathered by a close study of the fossil forms found in the rocks. All of Michigan 

 was raised above the ocean level at the close of the Ancient time, and so all our 

 rocks belong to that era. Consequently all the fossil remains which reward the 

 geological tourist and collector of Michigan will be of an old type. Much of 

 our gulf and western territory belongs to the middle life time. While the 

 Atlantic and Gulf shores and not a little of the great western plains belong to 

 the recent time. The collections found on our western confines are wonderful. 

 Skeletons of reptiles over 100 feet have beeu found in Kansas. While the 

 skeletons of birds and mammals show that a much more varied and extensive 

 life had existed upon our American continent previous to its discovery by 

 Columbus than was found here by the white men who came to take ])OSsession. 

 Very likely the red men were active agents in the destruction of the earlier 

 life, as they themselves are being exterminated by the more intelligent invaders 

 — the white men. 



Now let us study our own State in the light of what geology has to offer as to 

 its fertility and consequent productiveness; and first let us briefly consider the 

 agents which have ground up and mellowed the rock soil, making it the most 

 important factor in the production of seed time and harvest. You all have 

 observed sufficiently to know that frost and wind alone could not make a deep 

 fertile soil. These agents soon bury the rocks and thus emasculate their own 

 power to mellow and pulverize the earth's strata. Two great agencies have 

 wrought out this great work of erasion and pulverization. The one, the wear- 

 ing, grinding action of water, we have opportunity to observe and study to-day, 

 after each rain storm. We all know how irresistible this force is. The Colo- 

 rado chasm, reaching down a mile iu depth, tells what a mighty agent it is in 

 the work of cutting into the earth's features and modifying its surface. The 

 present contour of our whole country — aye of the whole world — is as left by the 

 hands of this great sculptor. All the hills, valleys, ravines, gorges which mark 

 the general configuration of our world home, as presented to the eye of the 

 tourist through any of our States or counties, are just as they haAC been left by 

 this ever working power, running water. As we see the little rill quietly flowing 

 through a considerable valley in almost every large field of the farm, it is hard 

 to believe that the one is the architect of the other. Yet we must remember 

 that the little rill is often swollen into a torrent, and that it has been working 

 for centuries; and thus in the lapse of ages it has been able to scoop out the 

 great valley, and to carry the earth to some lower level. The other force, 

 though a less general one, has been even more active in the past. It is that of 

 moving ice. In Greenland and Switzerland, and even ou our own Mount Hood 

 we see this stupendous force in action to-day. The traveler iu Switzerland can 



