ANNIVEBSARY ADDRESS OF THE rRESIDENT. XXXI 



during, is reflected in the pages of his book ; and I may safely aver, 

 from my own having- coincided, a few years later, with a part of his 

 North-western route, that his descriptions are accurate, and his con- 

 clusions, both on natural phenomena and on the social state of the 

 people, moderate and replete with common sense. 



Some critical expressions which fell from M. TchihateheiF, induced 

 Mr. Hamilton at a later date, in 1849, to recur to the subject, and 

 to present to the Society observations on the geology of Asia Minor, 

 referring more particularly to portions of (xalatia, Pontus, and Pa- 

 phlagonia. 



On his return to England he resumed his post as Secretary of the 

 Society, and, notwithstanding his being in Parliament from 1841 to 

 1847, he continued for many years to act in that capacity, applying 

 to it so much time and attention that he became the chief authority 

 with the Council in all questions that related to the constitution, the 

 bye-laws, and the history of the Society. 



Meanwhile a number of descriptive papers issued from his pen : — 



In 1844, a long and general treatise on the rocks and minerals of 

 that technically important part of Tuscany which lies between 

 Arezzo and Leghorn, and includes the boracic-acid springs, the 

 copper-mines, and the alabasters of Volterra. 



In 1848, an account of the agate- quarries of Oberstein and of the 

 methods of treating the agates artificially for the purpose of changing 

 their colour. 



In 1850, on the occurrence of a freshwater bed of marl in the 

 JFens of Cambridgeshire. 



For several years he had taken a lively interest in the progress 

 of the long somewhat weakly Geographical Society, and in 1837 

 was elected to be its President, an honour which he afterwards held 

 during the years 1841, 1842, and 1847. 



The most elaborate paper which Mr. Hamilton contributed to our 

 Quarterly Journal was that on the Geology of the Mayence Basin, 

 read in 1854. This detailed description of the remarkable alter- 

 nations of marine and freshwater Tertiaries extending more or less 

 from Wiesbaden by Mayence to Diirkheim is followed by theoretical 

 considerations explanatory of the changes which have introduced and 

 then checked the growth of a marine fauna in the midst of the Con- 

 tinent. And the character of some of the moUusca straightway 

 suggested to the author that during the Middle Tertiary period a 

 depression of such a nature must have taken place as to open a 

 communication between this region and the Mediterranean, to be 

 afterwards closed again, probably at the time when a movement of 

 elevation succeeded to the great and long- continued depression which 

 had permitted the accumulation of thousands of feet in thickness of 

 marine strata in North Switzerland. 



In the same year Mr. Hamilton was elected President of the 

 Society, on the occasion of Edward Eorbes being called away from 

 London to take the Professorship at Edinburgh. A short residence 

 on the E-hine had made the new President acquainted with Eridolin 

 Sandberger and others of the West-German geologists, and mth the 



