96 Mr. Lyell on a recent Formation of Freshwater Limestone, Sfc. 



5. Shell from Calcaire Grossier, Grignon . plentiful. 



6. Chalk, from stratum without flints, from Culver Cliff, Isle of Wight slight. 



7. Portland rock with shells plentiful. 



8. Transition limestone from Dudley, with trilobite slight. 



9. Gray slate from transition series, Forfarshire slight. 



10. Limestone imbedded in gneiss, from Glen Isla, Forfarshire slight. 



11. Ditto, Glen Isla, Forfarshire slight. 



The two last specimens of primitive limestone yielded no signs of ammonia until pulverized. 

 As its occurrence in these is remarkable, it is possible that water percolating the rock 

 may have conveyed down a slight quantity of ammonia, since the specimen examined 

 was not far distant from the surface. 



12. Carrara marble afforded no signs of ammonia. 



