NOVBMBBE 16, 1900.] 



SCIENCE. 



747 



science ; he severed it from cosmogony, for 

 which he entertained and expressed the 

 most profound contempt, and from the mu- 

 tilation thus inflicted geology is only at 

 length making a slow and painful recovery. 

 Why do I dwell on these facts? To depre- 

 ciate Lyell? By no means. No one is 

 more conscious than I of the noble service 

 which Lyell rendered to our cause ; his 

 reputation is of too robust a kind to suffer 

 from my unskilful handling, and the fame 

 of his solid contributions to science will en- 

 dure long after these controversies are for- 

 gotten. The echoes of the combat are al- 

 ready dying away, and uniformitarians, in 

 the sense already defined, are now no more ; 

 indeed, were I to attempt to exhibit any 

 distinguished living geologist aa a still sur- 

 viving supporter of the narrow Lyellian 

 creed, he would probably feel, if such a one 

 there be, that I was unfairly singling him 

 out for unmerited obloquy. 



Our science has become evolutional, and 

 in the transformation has grown more com- 

 prehensive ; her petty parochial days are 

 done, she is drawing her provinces closer 

 around her, and is fusing them together into 

 a united and single commonwealth — ^the 

 science of the earth. 



Not merely the earth's crust, but the 

 whole of earth-knowledge is the subject of 

 our research. To know all that can be 

 known about our planet, this, and nothing 

 less than this, is its aim and scope. From 

 the morphological side geology inquires, 

 not only into the existing form and struc- 

 ture of the earth, but also into the series 

 of successive morphological states through 

 which it has passed in a long and changeful 

 development. Our science inquires also 

 into the distribution of the earth in time 

 and space ; on the physiological side it 

 studies the movements and activities of our 

 planet ; and not content with all this it ex- 

 tends its researches into etiology and en- 

 deavors to arrive at a science of causation. 



In these pursuits geology calls all the other 

 sciences to her aid. In our commonwealth 

 there are no outlanders ; if an eminent 

 physicist enter our territory we do not be- 

 gin at once to prepare for war, because the 

 very fact of his undertaking a geological 

 inquiry of itself confers upon him all the 

 duties and privileges of citizenship. A 

 physicist studying geology is by definition 

 a geologist. Our only regret is, not that 

 physicists occasionally invade our borders, 

 but that they do not visit us oftener and 

 make closer acquaintance with us. 



EARLY HISTORY OF THE EARTH : FIRST 

 CRITICAI, PERIOD. 



If I am bold enough to assert that cos- 

 mogony is no longer alien to geology, I may 

 proceed further, and taking advantage of 

 my temerity pass on to speak of things once 

 not permitted to us. I propose, therefore, 

 to ofier some short account of the early 

 stages in the history of the earth. Into its 

 nebular origin we need not inquire — that 

 is a subject for astronomers. We are con- 

 tent to accept the infant earth from their 

 hands as a molten globe ready made, its 

 birth from a gaseous nebula duly certified. 

 If we ask, as a matter of curiosity, what 

 was the origin of the nebula, I fear even 

 astronomers cannot tell us. There is an 

 hypothesis which refers it to the clashing 

 of meteorites, but in the form in which this 

 is usually presented it does not help us 

 much. Such meteorites as have been ob- 

 served to penetrate our atmosphere and to 

 fall on to the surface of the earth prove on 

 examination to have had an eventful his- 

 tory of their own of which not the least 

 important chapter was a passage through 

 a molten state ; they would thus appear to 

 be the products rather than the progenitors 

 of a nebula. 



We commence our history, then, with a 

 rapidly-rotating molten planet, not impos- 

 sibly already solidified about the center and 



