174 THE SCIENCE OF BIOLOGY 



Hutton's ideas of volcanic action, of weathering, erosion, 

 deposition, and uplift were those which have been elaborated 

 by modern geology. His point of view was in every respect 

 scientific. His work constituted the foundation of British 

 geology. Hutton was followed by William Smith (1769- 

 1839) who is called the " Father of English Geology." The 

 latter showed, in his "Strata as Identified by Organized 

 Fossils," that the layers of the sedimentary rocks may be 



Shtch oft/vSuccefsion of STfiyf Tsi and tAur- nlative Altitudes 



Fig. 23. William Smith's Geological Section across the South of England. 

 Exaggeration of the vertical scale makes the beds appear too steep. The 

 original drawing was in colors. (From Scott, "Land Mammals of Western 

 Hemisphere," published by the Macmillan Co. Reprinted by permission.) 



identified by their fossils. This principle, which Smith 

 applied in his geological sections across England (Fig. 23) 

 has since been extended by geologists, until the correlation of 

 the sedimentary rocks on different continents has been 

 effected by extended applications of the methods he laid 

 down. 



During the early years of the nineteenth century, the 

 theory of creation, as applied to the earth's surface, was 

 changed into what was known as the Theory of Catastro- 

 phism. According to this theory, the earth was supposed to 

 have evolved through a series of creations, between each of 

 which fife flourished until destroyed by a great catastrophy 

 which was the prelude to a new creation. The catastro- 

 phism hypothesis was developed to meet two facts that 

 were irreconcilable with the theory of a single creation: 

 the discovery that animals of the past were unlike those 

 of the present; and the discovery that the dissimilarity in- 



