222 Zoological Society. 



follows the same law as in agates, entering their cavities by infiltra- 

 tion. 



The Author now gives a general Sketch of the various Rocks that 

 are known to usj he remarks that the Primary differ chemically from 

 the Secondary, and endeavours to account for the phenomena con- 

 nected with animal and vegetable life, as exhibited in the several for- 

 mations, upon the theory of a gradual Loss of Heat by Radiation. Upon 

 this theory he would explain the Scanty Supply of Limestone in the 

 earliest Rocks. The effect of great heat would be to expel from water 

 the carbonic acid necessary to hold the carbonate of lime in solutions ; 

 and consequently Calcareous matter could not be deposited from 

 heated water. He observes also that the Conditions for an uniform 

 distribution of animal and vegetable life, would be more uniform in a 

 thermal than in our actual Seas, and, therefore, if the Ocean had be- 

 come gradually cooler, we should expect to find, as we do, genera and 

 species more diversified. 



The terms, Eocene, Miocene and Pliocene, are objected to, as pre- 

 judging »n important question. Unless equal conditions obtained at 

 equal times in all places, the Miocene rocks of one country may be 

 of the same date as the Pliocene of another. The Author closes his 

 remarks on Erratic Blocks by observing, that, like the great contor- 

 tions and dislocations of strata, they teach us, while we duly appre- 

 ciate the continued and more tranquil effects which are daily before 

 our eyes, that we must not dismiss from our consideration Forces of 

 greater Intensity j still bearing in mind, that however great these 

 last-mentioned forces may be when measured by the ideas commonly 

 entertained on such subjects, they are still insignificant when consi- 

 dered with reference to the entire spheroid on the surface of which 

 they act. 



Gentlemen, I have now brought to a close the account, which, in 

 conformity with the practice of the Society, I proposed to lay before 

 you, of the labours and achievements oflast year. It therefore only 

 remains for me to resign the chair. When I consented to resume 

 the office of President, many of you are aware that a consciousness of 

 the precarious state of my health made me diffident of my powers to 

 discharge that office with becoming energy and effect. The generous 

 support which I have received from the Council and the Fellows at 

 large, has, I am willing to believe, in some degree concealed from your 

 observation several deficiencies, of which I myself have been fully 

 aware, and the Society has continued to flourish. The only merit I 

 claim is, that of having, upon all occasions endeavoured to promote 

 your interests j but a brighter prospect now opens upon you, and you 

 will find an ample guarantee for more brilliant anticipations of success 

 in the youth, the spirit, the abilities and the character of my suc- 

 cessor. 



ZOOLOGICAL SOCIETY. 



February 10. — A Letter was read, addressed to the Secretary by 

 W. H. Rudston Read, Esq., giving an account of the habits of the 

 Hyrax Capensis, Pall., as observed at the Cape of Good Hope, and 



