i8 EXTINCT MONSTERS 



at first, but the proofs are quite convincing. 1 As Professor 

 Huxley well remarked, there is as good evidence that chalk has 

 been built up by the accumulation of minute shells as that the 

 Pyramids were built by the ancient Egyptians. 



The science of geology reveals the startling fact that all the 

 great series of the stratified rocks, whose united thickness is over 

 80,000 feet, has been mainly accumulated under water, either by 

 the action of those powerful geological agents rain and rivers 

 or through the agency of myriads of tiny marine animals. When 

 we have grasped this idea, we have learned our first, and perhaps 

 most useful, lesson in geology. 



Now let us apply what- has been above explained to the 

 question immediately before us. We want to know how the 

 skeletons of animals living on land came to be buried up under 

 water, among the stratified rocks that are to be seen all over our 

 country, and most of which were made under the sea. 



We can answer this question by going to Nature herself, in 

 order to find out what is actually going on at the present time, 

 by inquiring into the habits of land animals, their surroundings, 

 and the accidents to which they are liable at sundry times and 

 in divers manners. It is by this simple method of studying 

 present actions that nearly all difficult questions in geology may 

 be solved. The leading principle of the geologist is to interpret 

 the past by the light of the present ; or, in other words, to find 

 out what happens now, in order to learn what took place ages 

 ago ; for it is clear that the world has been going on in the same 

 way for at least as far back as geological history can take us. 

 There has been a uniformity, or sameness, in Nature's actions 

 ever since living things first dwelt on the earth. 



Just as rivers are mainly responsible for bringing down to the 

 1 See the writer's Autobiography of the Earth, p. 223. 



