6 A Befrosjjcct of Geology for Forty Years. 



Eiver development attracts much attention, and S. S. Buckman- 

 leaves bis Ammonites and his ' Hemera ' to take part in the dis- 

 cussion. The subject was introduced in a paper on Bala Lake and 

 river system by Philip Lake, and Callaway contributes articles on> 

 the general question, while W. M. Davis writes on the peneplain of 

 the Scottish Highlands and discusses the meanders of rivers. 



The ancient glacier-dammed lakes of the Cheviots are described 

 by Kendall and Muff, while Bonney writes on moraines and mud- 

 streams in the Alps. Parkinson discusses the origin of certain 

 Canadian Lake-basins. Eock-basins, indeed, come in for considerable 

 notice. 



Watts deals with the ancient rocks of Charnwood Forest and 

 their physiography, and Mellard Reade continues to discourse on 

 mountains. 



Among general papers those by Cowper Reed on the Geology of 

 Waterford, and by Beadnell, Barron, and Hume on Egypt, may 

 be mentioned. 



Our old friend Rupert Jones gives a full Histoiy of Sarsens. 



The subject of Geological Photographs is brought prominently 

 into notice by Watts, and a number of excellent examples are 

 reproduced. Judd gives an interesting history of the earlier British 

 geological maps. 



Finally, much attention is again given to Geological Time, the 

 question having been consiclered by Joly in reference to the circu- 

 lation of salt. Sir A. Geikie deals generally with the subject in his 

 address to the British Association. 



Turning to the topics that are occupying much attention at the 

 pi'esent day, we find that the chief discussions are on subjects some- 

 what similar to those mentioned by Professor Rupert Jones in the 

 first number of the Magazine. The origin of the crystalline schists, 

 the genesis of rivers and the formation of their valleys, the 

 excavation of lake-basins, the correlation of strata by means of 

 special assemblages or zones of fossils, and the evolution of species 

 are subjects which engage continued attention and upon which 

 much has yet to be learnt. 



Throughout the history of the Magazine, now one topic, now 

 another has become dominant for a time. The relative importance 

 of marine and subaerial denudation, the origin and development of 

 rivers, the formation of crush-conglomerates, and the subject of 

 dynamic metamorphism are instances. But if these subjects have 

 again and again been brought forward, it is because someone gives 

 the key to what was previously an enigma, and many are ready to 

 use it ; or another has gained a position from which a clearer view 

 of a subject has been gained. From every fresh summit our ideas 

 of the expanse of unacquired knowledge are constantly enlarged — 

 a statement which is well known to apply to every branch of 

 learning — and this being the case there is a constant demand for 

 careful, earnest observers and workers, and there should be a constant 

 demand for the Geological Magazine. 



{To he continued.) 



