86 PEOP. J. LOGAN LOBLEY, F.G.S., ETC., ON 



aroimd a constant axis, and its consequent deviation from 

 the spherical to the spheroidal figure ; and, subsequently 

 and finally, the logs of one-eightieth of its bulk by the 

 separation by centrifugal force of its equatorial, exterior, 

 protruding portion, with the resulting formation of the 

 moon. 



The Second Period saw tlie solidification of the exterior 

 by cooling, the consistentior status of Lord Kelvin, by Avhich 

 the first permanently sohd rocks of the globe were formed; 

 the furrowing or wrinkling, and local depressing of the 

 surface by shrinkage ; the cooling of the hot and heavy 

 vaporous atmosphere, with the consequent condensation of 

 the water-gas (H^O) ; the gradual filling of the surface 

 hollows with the water so condensed, and the consequent 

 formation of the primasval seas and oceaiis of the globe ; 

 also the commencement of the destruction of the first-formed 

 land by the continuous and heavy rain highly charged with 

 acids, and the transportation of the eroded material and its 

 deposition beneath the waters of the first-formed seas. 

 Thus Avould be accumulated vast thicknesses of sedi- 

 mentary rocks to be afterwards melted by interior heat 

 or transformed in character by metamorphosing agencies. 



The Third Period saw the commencement of organic life 

 following on the establishment of the necessary normal 

 atmospheric and land conditions. With variations of 

 temperature between 32° F. and 212° F., winds would 

 be produced, with evaporation and precipitation of wa.ter, 

 that would give rise to storms, rain, and rivers, and so 

 denudation and the formation of sedimentary rocks would 

 be continued. The earlier of these rocks would also 

 afterv/ards be largely metamorphosed and any organic 

 remains entombed in them obliterated ; but they are the 

 foundation stones of the vast pile of stratified and fossili- 

 ferous rocks of later ages. 



This Third Period, therefore, witnessed the accumulation 

 of the stratified rocks and the innumerable generations of 

 animals which have successively inhabited the globe, with 

 the introduction of higher and higher forms, or organisms of 

 greater and greater complexity ; and Avitnessed, too, the 

 production of those great physical features of mountains, 

 valleys, and variously indented coast lines which now 

 diversify the land areas of the globe. And along with 

 all this animal life and these geological results, there was 

 the growth of plants, at first lowly cryptogamic organisms^ 



