ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxvii 



standard of geological philosophy, the ' Principles of Geology,' by 

 Sir Charles Lyell, has reached a ninth edition, one carefully and 

 learnedly brought up to the ever-increasing knowledge of our day. 

 A second edition has appeared of the ' Geological Observer,' a 

 volume in which Sir Henry De la Beche embodies the fruit of 

 years of fieldwork and reflection. A new elementary work of pe- 

 culiar merit, entitled ' Popular Physical Geology,' has come from the 

 pen of Mr. Jukes : this little book may be studied with advantage 

 by the most experienced, and, keeping as it does, in a style highly 

 commendable for perspicuity and nerve, the leading physical laws 

 and facts of the science before the reader, unmixed with palseontolo- 

 gical statements and conclusions, will serve as a wholesome corrective 

 of a tendency to regard too exclusively its biological aspects, a bias 

 on the part of geologists which a naturalist holds quite as much in 

 dread as the sternest mineralogist or dynamical observer. A useful 

 companion to elementary treatises in tlae form of an engraved table 

 of the characteristic fossils of the several formations has been sent 

 forth by Mr. Lowry. A new edition of Professor Pictet's ' Manual 

 of Palseontology,' by far the best work of its kind, is a welcome con- 

 tribution to our geological libraries ; and the same may be said of 

 Professor Philhps's ' Geology,' and of the lamented Dr. Mantell's 

 ' Medals of Creation,' edited by Mr. Rupert Jones. Among ele- 

 mentary works that have appeared on the continent is one by the 

 illustrious veteran Omalius D'Halloy, and in America Professor Hitch- 

 cock and Messrs. Adams and Gray have sent forth introductory 

 treatises. 



Conclusion. 



In the course of this Address I have used some expressions that, 

 as far as I am aware, are new to geological language, and involve an 

 idea which, although hypothetical, I wish to put forth upon this oc- 

 casion. I am strongly impressed with the belief, that, fanciful though 

 it may seem, there is within it the germ of a great geological truth, 

 I have spoken of genera concentrating towards the palaeozoic pole, 

 and vice versa, of the substitution of groups, and the opposition of 

 the more ancient to the mesozoic and modern faunas. The phrases 

 have been incidental, and arose naturally out of the subjects under 

 commentary, but the idea that lies at the base of them, whether true 

 or fallacious, requires to be stated, and there cannot be a better oppor- 

 tunity than the present for venturing to start this fresh geological 

 hare. 



Every geologist whose studies have been equally or nearly equally 

 directed to the organic phsenomena of the three great sections of time 

 usually received. Palaeozoic, Mesozoic, and Tertiary or Cainozoic, can- 

 not fail to have been struck with the greater value of the difference 

 between the first or oldest section and the two newer divisions taken 

 together, than between the first and middle terms and between the 

 latter and the last. The degree of organic difference between the 

 upper mesozoic and the lower tertiary epochs is rather more, but 

 only slightly more, than the degree of difference between the lower 



