98 



PROF. J. LOGAN LOBLEY_, F.G.S., F.R.G.S.^ ON 



of the deviation from spheroidicity of the earth since the solidi- 

 fication of its exterior could not be granted. Two other assump- 

 tions, the secular cooling of the globe and the expenditure of the 

 sun's heat, I ventured to contend, could not be allowed either, 

 for, as I then wrote, " we know little of the interior constitution 

 of the sun, and that therefore we are ignorant as to whether 

 there may not be some process by which the solar heat is 

 maintained," and that in the so-called new star, "Nova Persei," 

 there was a reminder that accessions of heat and light by suns 

 might be received at any period of their existence, and if in this 

 case tlie accession was sudden and great, he would be bold 

 indeed who would say that an accession of heat and light might 

 not be given slowly and to a small extent. Since then the 

 discovery of radium has supported this hypothetical contention. 



The physical estimates ignore the facts of geology, yet it must 

 be admitted, I think, even by pure physicists themselves, that 

 the bases of such estimates are more assumptive, more open to 

 dispute, are less clearly established and less substantial facts, 

 and therefore more uncertain and less reliable than are the 

 grounds on which are based geological estimates. To again 

 quote Geikie: "The geological record furnishes a mass of 

 evidence which no arguments drawn from other departments of 

 Nature can explain away, and which, it seems to me, cannot be 

 satisfactorily interpreted save with an allowance of time much 

 beyond the narrow limits which recent physical speculation 

 would concede." 



Biological Change. 



Probably during nearly the whole of geological time, 

 biological change has been going on, for in the Lower Cambrian 

 rocks there are the remains of highly developed animals, 

 pointing to, if not demonstrating, the previous existence during 

 the Pre-Cambrian epoch of lower or simpler organisms, although 

 none have hitherto been with certainty discovered in the rocks 

 of that early period of the world's history. This inference is 

 strongly supported by the fact that in the Pre-Cambrian rocks 

 are limestones and masses of graphite, the limestones pointing to 

 the Pre-Cambrian existence of animal life and indirectly to 

 that of plant life, while the graphite points directly to a Pre- 

 Cambrian terrestrial flora, lint leaving out of consideration 

 this Pre-Cambrian epoch, the rocks of which have not yet 

 yielded decided fossils, and taking only the time from the 

 commencement of the Cambrian periotl, in the lower rocks of 

 which are well-preserved remains of highly developed animals, 



