12 Missing Chapters of Geological History. 



MISSING CHAPTERS OF GEOLOGICAL HISTORY. 



BY PROFESSOR D. T. ANSTED, F.R.S. 



Under the title ' ' Imperfection of the Geological Record" there 

 is a striking and suggestive chapter in Darwin's Origin of 

 Species, one result of which perhaps shows itself in the two 

 anniversary addresses to the Geological Society, delivered by 

 the President, Professor Ramsay, in the years 1863 and 1864. 

 In these addresses the breaks in succession, or unconformities 

 in the older and secondary strata, are considered with some 

 care, the author connecting strati graphical breaks with inter- 

 ruptions of the continuity of life and the converse. 



In one sense it has always been admitted, by geologists and 

 naturalists, that as the existence at a given time and in a given 

 place of a certain group of animals or vegetables is, at the least, 

 a proof of the general mutual fitness of the habits and struc- 

 tures of the organic to the conditions of inorganic existence, so 

 any great change in the inorganic conditions must involve a 

 corresponding change in the organic inhabitants. No doubt 

 the interpretation of such a statement has been different by 

 different writers, some assuming and endeavouring to prove 

 that important change, either organic or inorganic, must be 

 abrupt, cataclysmal, and manifest ; while others believe that 

 something inherent in the individual organism has during all 

 time induced a modification of individuals and races as circum- 

 stances have rendered change desirable. 



There was not wanting a certain amount of angry and 

 alarmed declamation when it was first suggested that Nature, 

 or rather the great Creator — the God of Nature — in the exercise 

 of his Almighty Power in creation, may perhaps have instituted 

 laws, the natural working out of which should result in a perpe- 

 tual adaptation to incessant change. This view, simple enough, 

 and certainly not tending to dishonour the Creator, but, on the 

 contrary, imputing to Him the highest and greatest wisdom, 

 cannot be regarded even now as generally admitted, but is 

 gaining ground, and is perfectly consistent with, though by no 

 means dependent on, a reception of the Darwinian doctrine of 

 development by natural selection. 



To discover the meaning and value of the breaks or inter- 

 ruptions that have taken place in the stratification even of a 

 single group of deposits in any one county, it is beyond a 

 doubt that the mind must be open to argument, and not hemmed 

 in by preconceived notions. Geology, more than most of the 

 natural history sciences, requires this condition of the intellect 

 — this willingness to receive truth in whatever form it may 



