Vol. 59.] THE ASHBOURNE AND BUXTON RAILWAY. 347 



of organisms among the oolitic rocks, and whether he attributed the 

 oolitic structures to the growth of Girvanelhi; The best instances of 

 oolite-formation at the present day occurred in closed salt-lakes ; he 

 had never seen true oolitic structure in association with coral- 

 reefs. 



Prof. Watts said that he was much impressed by the Author's 

 microphotographs of dolomitic limestone. There was no more 

 remarkable phenomenon than the growth of dolomite in rocks 

 of this kind. The magnesia appeared sporadically in the midst of 

 oolitic grains, and there was a most interesting zonary arrangement 

 of impurities inside the dolomite-crystals. 



The Author said that encrinite-stems occurred in some of the 

 oolitic grains, and thanked the Fellows for the reception accorded 

 to his paper. 



2 b* 



