. BY K. M. JOHNSTON, F.L.S. 146 



conclusions and the inductions drawn from them are not 

 based upon foundations as assured as those of other 

 branches of geology and palaeontology." 



The following table not only helps us to understand the 

 different opinions of authorities at different times with 

 respect to the classification of well known typical forma- 

 tions of England, but it is an index of the uncertainty of 

 fixing many hard-and-fast subdivisions which would prove 

 suitable for widely separated locahties. 



