470 Reports and Proceedings — 



times. Under such circumstances geology would indeed be an uncertain 

 science, and we should labour in the field knowing that a satisfactory 

 earth-history would never be written. Let us hope that a brighter future 

 is in store for us, and let me urge my countrymen to continue to study 

 the minute subdivisions of the strata, lest they be left behind by the 

 geologists of other countries, to whom the necessity for this kind of 

 study is apparent, and who are carrying it on with great success. 



The value of detailed work on the part of the stratigraphical geologist 

 is best grasped if we consider the recent advance that has been made in 

 our science owing to the more or less exhaustive survey of the strata of 

 various areas, and the application of the results obtained to the elucidation 

 of the earth's history. A review of this nature will enable us not only to 

 see what has been done, but also to detect lines of inquiry which it will be 

 useful to pursue in the future ; but it is obvious that the subject is so 

 wide that little more can be attempted than to touch lightly upon some 

 of the more prominent questions. A work might well be written treating 

 of the matters which I propose to notice. We have all read our " Prin- 

 ciples of Geology," or " The Modern Changes of the Earth and its inhabi- 

 tants considered as illustrative of Geology," to quote the alternative title ; 

 some day we may have a book written about the ancient changes of the 

 earth and its inhabitants considered as illustrative of geography. 



Commencing with a glance at the light thrown on inorganic changes by 

 a detailed examination of the strata, I may briefly allude to advances 

 which have recently been made in the study of denudation. The minor 

 faults, which can only be detected when the small subdivisions of rock- 

 groups are followed out carefully on the ground, have been shown to be 

 of great importance in defining the direction in which the agents of 

 denudation have operated, as demonstrated by Professor W. C. Brogger, 

 for instance, in the case of the Christiania Fjord 1 ; and I have recently 

 endeavoured to prove that certain valleys in the English Lake District 

 have been determined by shattered belts of country, the existence of 

 which is shown by following thin bands of strata along their outcrop. 

 The importance of the study of the strata in connection with the genesis 

 and subsequent changes of river-systems is admirably brought out in 

 Professor W. M. Davis's paper on " The Development of certain English 

 Rivers," 2 a paper which should be read by all physical geologists ; it is, 

 indeed, a starting-point for kindred work which remains especially for local 

 observers to accomplish. Study of this kind not only adds to our know- 

 ledge of the work of geological agencies, but helps to diminish the 

 imperfection of the record, for the nature of river-systems, when rightly 

 understood, enables us to detect the former presence of deposits over 

 areas from which they have long since been removed by denudation. 



An intimate acquaintance with the lithological characters of the strata 

 of a district affords valuable information in connection with the subject 

 of glacial denudation. The direction of glacial transport over the British 

 Isles has been largely inferred from a study of the distribution of boulders 

 of igneous rock, whilst those of sedimentary rock have been less carefully 

 observed. The importance of the latter is well shown by the work which 

 has been done in Northern Europe in tracing the Scandinavian boulders 

 to their sources, a task which could not have been performed successfully 

 if the Scandinavian strata had not been studied in great detail. 3 I shall 



1 "W. C. Brogger, Nyt. Mag. for Naturvidensk., vol. xxx (1886), p. 79. 



2 W H M. Davis, Geograph. Jourii., vol. v (1895), p. 127. 



3 It is desirable that the boulders of sedimentary rock imbedded in the drifts of 

 East Auglia should be carefully examined, and fossils collected from them. The 

 calcareous strata associated with the Alum Shales of Scandinavia and the strata of 

 the Orthoceras Limestone of that region may be expected to be represented amongst 

 the boulders. 





