i86 3 ADDRESSES AND LECTURES 277 



he connected these gaps with geographical changes of 

 which no other trace had survived. He had made a 

 communication on this subject to the American Asso- 

 ciation at the Montreal meeting, which had attracted 

 considerable attention among those present. He had 

 afterwards made it the subject of one of his evening 

 lectures to working men at Jermyn Street. But no 

 full exposition of his views had yet been made public. 

 He therefore chose ' Breaks in the Succession of the 

 British Strata' as the thesis to be worked out in 

 his two successive presidential addresses, taking the 

 Palaeozoic systems in the first year (1863), and the 

 Secondary and Tertiary systems in the second (1864). 

 Some account of these essays will be given in the con- 

 cluding chapter of this volume. 



In the months of January and February 1863 Ramsay 

 gave a course of six evening lectures to working men in 

 the Jermyn Street Museum on the Physical Geology 

 and Geography of Great Britain. These lectures were 

 taken down at the time in shorthand, and were shortly 

 afterwards printed and published as a small volume. 

 Unfortunately, the lecturer's state of health at the time 

 prevented him from correcting the proofs with ade- 

 quate care. The book consequently appeared full of 

 inaccuracies. But the nucleus of a valuable handbook 

 was there, and in later years its author was able to 

 revise and enlarge it, and it now forms his well-known 

 and admirable treatise on the Physical Geology and 

 Geography of Great Britain. Even in the original 

 tract the geological reader can perceive the outlines 

 of many deductions regarding the growth of the sur- 

 face topography of the land, which the author was able 

 subsequently to work out more fully. The publication 

 of this book marks a distinct epoch in its writer's 



