310 Doubts Relative to the Epochal and 



liquidity be produced by a degree of heat of far greater in- 

 tensity than can possibly be produced on the surface. 



Under such conditions of heat, and allowing with Dr. 

 Young that " at the earth's centre, steel would be com- 

 pressed into one-fourth and stone into one-eighth of its 

 bulk,"* yet, as the heat is still increasing as the centre is 

 neared, it is difficult to conceive how molecular attraction 

 could resist the expansive power of heat, and that any 

 other than a perfect fluid of a homogeneous nature, and of 

 no very great specific gravity,* occupies a very considerable 

 portion of the earth's interior ; the researches of Airy and 

 Hopkins have gone far to determine such a condition. 



In contrast with this conclusion, and also with that now 

 very generally adopted, of the earth having once been a fluid 

 or molten mass moving in its orbit as a fiery meteor, the two 

 following facts relative to the earth's surface appear to be in 

 direct opposition. 



ist : From whatever point of view the internal heat of the 

 earth is measured, the external area of the globe cannot be 

 more contracted than it has been for ages past, for the 

 amount of unconformity in the sedimentary rocks is less in 

 proportion, so far as observation has yet extended, to the 

 amount of disruption of granite, or of irruptive rocks, since 

 such sedimentary rocks have been formed ; which circum- 

 stance bespeaks rather an increase than a decrease of the 

 earth's superficial area. Moreover, the general elevation of 

 the sedimentary rocks from the time of the metamorphic 

 rocks until now, as shown by the increase of LAND plants 

 and animals, especially AFTER the formation of the Cum- 

 brian, Cambrian, and Devonian systems, all tend to the 

 same conclusion. For during their formation the almost 

 total absence of land organic remains, and, in some parts, 

 the great abundance of marine remains, attest the univer- 



* Lyell's " Principles of Geology," 8th edit., page 515. 



