GEOLOGY. 95 



materials of decomposed rocks. These are termed Di- 

 luvial and Alluvial, and are sometimes indifferently used, 

 but the Diluvial are more properly those which indicate 

 a remote origin, and the Alluvial a more recent forma- 

 tion. These deposits are sometimes as much as 20 or 30 

 feet in depth. Over these lies the soil which is com- 

 posed of sand mixed with decayed animal and vegetable 

 matter. 



In order to form the various depositions an immensity 

 of time must have been required; thousands and tens 

 of thousands of years must have passed by while these 

 stupendous changes were being effected. Whether these 

 repeated submersions were caused by the sinking and 

 upheaving of the land, or whether they were the result 

 of astronomical causes,* the length of time employed 

 must have been immense. Changes are still going on 

 on the Earth's surface, slow, it is true, but continuous. 

 When the Earth had become in a proper state for the 

 reception of a more noble inhabitant, Man was created. 



Having thus traced the Earth from the most remote pe- 

 riods to the present time, it may be observed, in conclu- 

 sion, that of all the sciences there is none more interesting 

 than Geology, and, as an eminent writer observes, in 

 vastness of extent, and sublimity of character, it yields 

 only to Astronomy. 



Sir R. Phillips ascribes the different formations to deposits caused 

 by the overflowing of the sea through the change of the line of Apsides, 

 and argues that to whatever hemisphere the sun may bein/ieri/ie/ion, the 

 centrifugal force will be greater there, and cause a greater elevation of 

 the waters of the ocean. As the perihelion is now very nearly south, 

 the waters of the southern hemisphere are more elevated than those of 

 the northern, and consequently there is proportionately less land ; and 

 this will continue to be the case until the perihelion comes round to 

 the northern hemisphere, when the land in that hemisphere will become 

 to a considerable extent submerged. As the line of Apsides takes about 

 21,000 years to perform a revolution through the ecliptic, Sir Richard 

 calculates that 600,000 years would be required for the formation of the 

 Transitive, Secondary, and Tertiary formations : an immensity of time; 

 but it must be remembered that with the Almighty a thousand years 

 are as one day. 



