Geological Society. 2 1 7 



zation would have been almost as interesting as the one show- 

 ing the difference between the muriates and chlorides, if they 

 could have been both established, as then we should have had 

 a much more convenient way of measuring the water of cry- 

 stallization than making an analysis, which, perhaps, would 

 be very complicated, and therefore much more liable to error. 



From the experiments contained in this paper, I think the 

 following conclusions may be drawn : — 



First, that when a salt dissolves in water, there is sometimes 

 a condensation and sometimes an expansion of the original 

 volume of the salt and water. 



Secondly, that the application of heat and the quantity of 

 water make a certain difference in the amount of condensa- 

 tion or expansion resulting from the solution of a salt. 



Thirdly, that in the case of the isomorphous salts especially, 

 when a class of them dissolve, they occasion an expansion or 

 condensation in a multiple ratio of the increase or diminution 

 of volume occasioned by the several atoms of those salts; and 

 that when a class of hydrous isomorphous salts made anhy- 

 drous combine with their requisite portion of water of cry- 

 stallization, the condensation then occasioned is also in a mul- 

 tiple ratio. 



Manchester, June 1845. 



XXXIII. Proceedifigs of Learned Societies. 



GEOLOGICAL SOCIETY. 



Feb. 26, \ PAPER was read by Mr. Lyell, " On the Miocene 

 1845. ■^'^ Tertiary Strata of Maryland and Virginia, and 

 North and South Carolina." 



These rocks of the middle tertiary period are chiefly exhibited 

 between the hill country and the Atlantic, and form a band of low 

 and nearly level country, almost 150 miles wide, and not 100 feet 

 high. They are assumed to belong to this period, because they are 

 seen resting on the eocene deposits, and exhibit about the same pro- 

 portion of recent species. The United States miocene beds consist 

 chiefly of incoherent sand and clay, and the sandy beds, otherwise 

 barren, have often been fertilized by the use of shell marl. In the 

 suburbs of Richmond, Virginia, there is however a remarkable bed 

 of siliceous sand, derived from the cases of infusorial animalcules. 

 The paper was accompanied by comparative tables and lists of the 

 fossils. 



A paper, also by Mr. Lyell, " On the White Limestone and 

 other Eocene Tertiary Formations of Virginia, South Carolina and 

 Georgia." 



The eocene beds extend chiefly to the south of the miocenes de- 

 scribed in the foregoing paper, and are very widely spread in the 

 Southern States on the shores of the Atlantic. The mineral character 



