lUP^ , THE ' T ^t 



QUARTERLY JOURNAL 



GEOLCKilCAL SOCIETY OF L0N1K)N. 



EDITED BY 



THE PERMAjS^ENT SECRETARY OF THE 



Quod si cui mortalium cordi et curae sit non tantum inve^tis usjf-i^eve, atque iis iitu,^3^a(^'ulteriora 

 penetrare ; atque non disputando adversarium, sed opere naturaniHij^re;^^qwili)S TOile^^fprobabiliter 

 opinari, sed certo et ostensire scire ; tales, tanquam veri scientiarum filnTtiubij {ai videWfur) se adjungant. 

 —Novu7)t Organum, Trafatio. 



VOLUME THE SEVENTY-THIRD, 



FOR 1917. 



LONDON : 

 LONGMANS, GREEN, AND CO. 



PAEIS: CHARLES KLINCKSIECK, 11 EUE DE LILLE. 



SOLD ALSO AT THE APARTMENTS OP THE SOCIETY, 



JICMXVIII. 



^ 



