GEOLOGY IN EVERYDAY LIFE MANSFIELD 271 



methods of estimating geologic time, though permitting more exact 

 statement of the lengths of individual periods or eras, emphasize the 

 great age of the earth in contrast with the brevity of recorded history. 

 Thus the age of the earth and the geologic record of the development 

 of life upon it furnish a background for religion, philosophy, and 

 social science. 



Geography, a subject included in practically every educational 

 program, rests on geology. The progress of life through the ages as 

 shown by the geologic record has depended largely upon geologic 

 conditions. Faunas have waxed and waned with the advance and 

 retreat of seas over continents. Floras and vertebrates have re- 

 sponded similarly to the movements of the great ice sheets. The 

 present distribution of plants and animals shows many peculiarities 

 owing to these agencies and to isolation of certain inhabited areas 

 from other corresponding areas by submergence or other geologic 

 causes. The fauna and flora of Australia are well-known examples. 

 The natural conditions that have favored the location of manufac- 

 turing or maritime cities, trade routes, and transportation lines are 

 generally traceable to geologic causes. 



History plays a great part in education. Many historical events 

 from earliest times have had a geologic background. Tribes and 

 nations have developed their own customs and habits according to 

 whether they lived in mountain glens or broad alluviated country ; on 

 continents or islands. Great civilizations have arisen at the mouths 

 or on the plains of great rivers. These favorable natural features 

 are the products of geologic agencies operating on rocks of different 

 kinds through long ages. 



According to trustworthy authorities, the great deluge of Biblical 

 days, as well as the devastating flood of this century at Galveston, 

 Tex., was the result of a chance combination of hurricane and tide 

 in low coastal and estuarine areas. 4 Mountain passes, products of 

 geological agencies, have helped or hindered movements of peoples 

 or armies. The Germans took advantage of the lowlands in Belgium 

 in beginning their first advance in the World War. Accounts of 

 battles have shown that the geologic nature of the terrain is always an 

 important factor in any victory or defeat. However, the great under- 

 lying causes of wars are economic and depend in large measure upon 

 the distribution of supplies of usable mineral raw materials whose 

 origin and distribution are geologic problems. 



The observation and study of nature is a prime element in any 

 modern educational program. Nature is so full of geology that one 

 can hardly look in any direction without seeing something of geologic 

 interest. Classes in nature study may have different objectives, but 



* The New England hurricane of September 1638 might be added here. 



