169 



bles are moistened with a solution of chloride of calcium, and 

 then placed in contact and heated, the chlorine of the chloride of 

 calcium escapes, and the oxide of calcium or lime unites with 

 the silex and forms silicate of lime. There could be no doubt 

 that the chloride of calcium was derived from sea-water. Some- 

 times in the vicinity of trap dykes, as at Purgatory, near New- 

 port, Rhode Island, specular iron ore, evidently derived from sub- 

 limation of oxide of iron from the chloride of iron, had invested 

 the pebbles with a thin crystalline film, which served as a cement. 

 He stated some experimental results of M. Gay Lussac, on subli- 

 mation of specular iron ore, from chloride of iron, and his obser- 

 vations on the production of this ore in the crater of Mt. Vesu- 

 vius ; experiments and observations which Dr. Jackson had 

 repeated and verified. 



The cementing materials of some sandstones are so largely 

 calcareous, that on removal of the carbonate of lime by the 

 action of acids, the stone crumbles into sand. In such sandstones 

 the carbonate of lime was probably infiltrated as a bi-carbonate, 

 and on losing one equivalent of carbonic acid, the carbonate of 

 lime would solidify in crystalline form and firmly unite the sand, 

 making it into a solid rock. 



If a sandstone, cemented by carbonate of lime, is exposed to a 

 high temperature, silicate of lime would be produced by combi- 

 nation of silex with the lime, and carbonic acid gas would be 

 disengaged. 



Dr. Henry Bryant called the attention of the Society 

 to some of the birds presented by the Royal Victoria 

 Society of Melbourne, Australia. 



Among them was a pigeon resembling more nearly the Phaps 

 elegans of Gould than any other species he had found described ; 

 but differing sufficiently from Gould's description to lead him 

 to believe that it might prove to be a new species. The dif- 

 ference consists in the present specimen having a whitish line 

 beneath the eye, not found in the P. elegans, and in the back 

 being a greenish brown, with slight metallic reflections, instead 

 of " deep, rich, lustrous chestnut," as described by Gould. 



One of the birds on the table did not belong to the Society, but 



