SCIENCE IN THE LAST HALF CENTURY. 97 



after time, highly organized types have been discovered in formations 

 of an age in which the existence of such forms of life had been confi- 

 dently declared to be impossible. The western territories of the United 

 States alone hav^e yielded a world of extinct animal forms, undreamed 

 of fifty years ago. And wherever sufiBciently numerous series of the re- 

 mains of any given group, which has endured for a long space of time, 

 are carefully examined, their morjihological relations are never in dis- 

 cordance with the requirements of the doctrine of evolution, and often 

 afford convincing evidence of it. At the same time, it bas been shown 

 that certain forms persist with very little change, from the oldest to the 

 newest fossiliferous formations ; and thus show that progressive devel- 

 opment is a contingent, and not a necessary result, of tbe nature of liv- 

 ing matter. 



GEOLOGY. 



Geology is, as it were, the biology of our planet as a whole. In so 

 far as it comprises the surface configuration and the inner structure of 

 the earth, it answers to morphology; in so far as it studies changes of 

 condition and their causes, it corresponds with physiology; in solar as 

 it deals with the causes which have effected the progress of the earth 

 from its earliest to its present state, it forms part of the general doc- 

 trine of evolution. An interesting contrast between the geology of the 

 present day and that of half a century ago is presented by the complete 

 emancipation of the modern geologist from the controlling and pervert- 

 ing influence of theology, all-powerful at the earlier date. As the geol- 

 ogist of my young days wrote, he had one eye upon fact and the other 

 on Genesis ; at present he wisely keeps* both eyes on fact and ig- 

 nores the pentateuchal mythology altogether. The publication of the 

 "Principles of Geology" brought upon its illustrious author a period 

 of social ostracism ; the instruction given to our children is based upon 

 those principles. Whewell had the courage to attack Lyell's funda- 

 mental assumption (which surely is a dictate of common sense) that we 

 ought to exhaust known causes, before seeking for the explanation of 

 geological phenomena in causes of which we have no experience. But 

 geology has advanced to its present state by working from Lyell's* 

 axiom ; and to this day the record of the stratified rocks affords no proof 

 that the intensity or the rapidity of the causes of change has ever varied 

 between wider limits than those between wbich the operations of nature 

 have taken place in the youngest geological epochs. 



An incalculable benefit has accrued to geological science from the 

 accurate and detailed surveys which have now been executed by skilled 

 geologists employed by the Governments of all parts of the civilized 



* Perhaps I ought rather to say Bnffon's axiom. For that great naturalist and 

 writer embodied the principles of sound geology iu a pithy phrase of the Th^orie de 

 la Terre : "Pour jnger de ce qui est arriv^, et meme de ce qui arrivera, nous n'avops 

 qu'a examiner ce qui arrive." 



H, Mis. GOO 7 



