INTRODUCTION. XV 



time, but beltjuged to many dittereiit periods of the earth's 

 history. Their destruction aud burial, therefore, could not 

 1)6 ascribed to any single great catastrophe. It was demon- 

 strated that during past ages the distrilnition of land and 

 sea, mountains and plains, had frequently changed — that, in 

 fact, rain, rivers, waves, currents, \'ol canoes, and phenomena 

 like earthquakes, were continually altering the earth's 

 surface, even under the eyes of man himself. Tiie fossils 

 were proved in most cases to be buried in displaced portions 

 of sea-l)ottom, and in the mud of dried-up lakes ; and it was 

 realised that the relative ages of these deposits could be 

 determined liy the order in which they lay one upon 

 another. Thus arose tlie true " science of the earth," which 

 was named Geology l)y De Luc in 1778. 



An English civil engineer, "William Smith (1769-18o9), 

 was perhaps tlie first to realise fully the possibilities of this 

 new ])raucli of learning. His i)rofessiou necessitated much 

 travel through the country, and his interest in the distri- 

 bution of fossils in the different kinds of rock led him to 

 make a large collection, which was acquired by the British 

 ]\Iuseum in 1816, and is now exhibited in Gallery No. 11 

 of the Department of Geology. His published maps and 

 writings pro\'e that the various features of the landscape, 

 in districts where fossils occur, are naturally carved out of 

 layers of rock, which are simply old sea-beds or lake-beds 

 piled one upon another, the oldest at the bottom, the newest 

 at the top, each containing its own definite and invariable 

 set of fossils. They also show that in most cases when these 

 old sediments were raised into dry land, they were tilted in 

 vaiious ways from their originally horizontal position ; so 

 tliat it is often possible in a short walk to pass over the cut 

 edges of many successi\"e layers, ])erhaps hundreds of feet in 

 thickness, representing immense periods of time. 



AVhile Smith and others were busily engaged in collecting 

 fossils and observing their distril)ution, lUumenliach, Cuvier, 

 Lamarck. Lrongniart, and other naturalists were occupied 

 with a detailed study of the fossils themselves. They soon 

 (U'moustrated tliat, while most of these petrified remaius 

 could be interpreted by comparing them with the life of the 

 present world, a large proportion represented animals and 

 plants no longer existing. They also o])served that the 

 older the fossils, the more strikingly different they were 

 from any animals and plants now living. It therefore 

 became evident that fossils attbrded a means of discovering 



