WHY WE SHOULD TEACH GEOLOGY. 75 



nally stratified, and packed with, the remains of living beings, 

 have been transformed into slates, schists, and other crystalline 

 rocks, and the inquiry, how this has been done, can only be an- 

 swered by the geologist. 



5. During the process of mountain-building the earth's crust 

 has been uplifted, shattered, or dislocated, and finally permeated 

 by hot springs, and the cracks and rents extending to the sur- 

 face filled with the precious minerals. Certainly there is good 

 reason why we should know how the ores thus came to be 

 brought up from the bowels of the earth and almost laid at our 

 doors. Theoretical geology gives us the probable explanation. 



6. Our North American continent has had a beginning, has 

 passed through a period of infancy, youth, and maturity; the 

 mountain-ranges bounding it are of different ages; its varying 

 climates have become gradually established, and at different 

 epochs it was fitted for the maintenance of quite different as- 

 semblages of plants and animals. The intimate relationship be- 

 tween these successive plant and animal worlds and the ground 

 on which they were born, flourished, and died is now tolerably 

 well understood by our geologists. 



7. Coal and coal-oils are geological products. Geologists can 

 now give a satisfactory account of just how coal-beds have been 

 formed from vast peat swamps ; why great beds of iron ore are 

 interstratified with the coal. We have only had our attention 

 drawn to coal-oils since 1860, but already our geologists feel 

 confident that they are due to the immense profusion of marine 

 animals or vegetables, or both, during the times before and since 

 the great Coal period ; and chemical geologists nearly all agree 

 in believing that petroleum is due to the storage in the earth of 

 the chemical products derived from the tissues and oily matters 

 once forming part of the bodies of myriads of living beings. 



8. It is interesting to know, and history-classes learn, the mode 

 of origin of the people of Greece, of Rome, of the making of 

 Great Britain, the mode of origin of the French or German peo- 

 ples, and the successive steps in the history of our own nation. 

 It is equally important to know when the worms, ascidians, 

 early vertebrates, and fishes made their appearance ; when it be- 

 came possible for air-breathing vertebrates to exist, and when the 

 forerunners of mammals and man, the amphibians, were evolved 

 from the ganoids. Paleontology throws light on these points, if 

 intelligently studied and properly taught. 



9. Much time is given in our schools to the memorizing of the 

 dates of the birth and death of kings and of dynasties. Why 

 should not the pupil also learn the geological date of the first 

 known appearance of mollusks, star-fishes, worms, insects, fishes, 

 reptiles, birds, and beasts ? There are a great many isolated 



