the ice period. The waters flowing through these gravel streams, 

 crop out at the border of the glacial drift and eroded val- 

 leys as springs, their source or fountain head being suffic- 

 iently elevated so that when borings are made along their 

 course, the result is a flowing well, and to which our city owes 

 its supply of pure water. 



From the close of the Palaeozoic era, or when the surface 

 of Indiana was permanently raised from the sea, to the com- 

 mencement of the glacial period, time was measured by mil- 

 lions of years. And during this long period the surface of 

 Indiana was transformed from a comparatively level, swampy 

 area into one of great river valleys, hills and buttes, table lands, 

 and all the varied scenery of a surface long exposed to aqueous 

 and subaerial solution and consequent erosion. Also the great 

 mountain chains of the west were given birth, and pushed their 

 towering heads toward the sky, and six miles in depth of some 

 of their rocky surfaces during this time disintegrated, eroded 

 and were again returned to the seas by mountain streams. 

 The upheaval of the several chains of mountains in the 

 west, the consequent elevation of adjoining surfaces, forming a 

 gradual decline to the east, meeting the gradual decline west- 

 ward from the Appalachian Mountains, draining the remainder 

 of the interior sea and constituting the great interior valley, 

 drained by the Mississippi and its tributaries, this gave to 

 the continent of North America largely its present geographi- 

 cal lines or contour. 



In a few words we have attempted to follow the conti- 

 nental changes which have occurred during a long period of 

 time, from the Archaean era. to the close of the Tertiary period. 

 The mere statement of those figures is appalling, and almost 

 incomprehensible. Conservative Geologists and Scientists, 

 estimate the lapse of time from the closing of the Archaean 

 era, to the end of the Palaeozoic, or until the appearance of the 

 Appalachian range, at fifteen millions of years, or one-half of the 

 time from the Archaean era to the present time, making a total 

 lapse of thirty millions of years since nature began the con- 

 struction of the North American continent, and fifteen millions 



