THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE II. VOL. V. 



No. IV.— APRIL, 1878. 



OI^I(3-XIS^.A.XJ j^e-tioXjIES. 



I. — The Age of the World as viewed by the Geologist 



AND the Mathematician. 



By T. Mellard Reade, C.E., F.G.S. 



TTNTIL Geology began to take the place of a science, few, if any, 



\_) troubled themselves about the age of our planet. The habit 



of thought, created partially by the Mosaic Cosmogony, which led 



us to look at all the natural features around us.as if but just freshly 



formed by the hands of the Creator was not favourable to any such 



inquiry. 



To think that everything, as we see it now, is as it always was, 

 is easy and natural, saves trouble, and is a habit of mind deeply en- 

 grained in human nature. It is only within the last few years that 

 we have been able to dispossess ourselves of this notion with regard 

 to animated nature. Special creation of everything as we see it 

 answers best to our anthropomorphic ideas, derived from a contem- 

 plation of man's creative efforts. The conception of innate energy, 

 continuity, and evolution, is a higher stage of thought, only arrived 

 at by close observation of, and reasoning on, the relations of natural 

 phenomena. 



So far as my knowledge of history extends, the geologist was the 

 first to raise the question of the Earth's age. Astronomy did not 

 lead to its contemplation. No one that I am aware of, before geolo- 

 gical inquiry, said the Earth must be so many millions of years old, 

 because the rate at which the temperature increases downwards 

 shows that it must at least have taken so long to cool from the time 

 when it was an incandescent globe. Yet it is the astronomer who 

 inferred long since that this Earth of ours, from its spheroidal form, 

 must originally have been in a molten state, and the same elements 

 existed at the time for the calculation of its age from a physical 

 basis that do now. Why then was it not done ? Simply because it 

 did not strike any one that it must be extremely ancient, as the 

 evidences of age did not come prominently forward. 



When, however, the curiosity of the geologist, delving into the 

 Earth's crust brought to light the fact that under thousands of feet 

 of rock lay the evidences of the existence, at an earlier period, of a 

 fauna and flora differing from those of the present day, — of rivers, 

 seas and continents now buried below deposits to which those 

 obscuring the remains of ancient Troy are as a film of dust, — it was 

 impossible any longer to resist the conviction that the age of the 



decade II. VOL. v.— NO. IV. 10 



