

n 



THE 



QUARTERLY JOURNAL 



GEOLOGICAL SOCIETY OF LONDON 



EDITED BY 



THE ASSISTANT-SECEETAEY OF THE GEOLOGICAL SOCIETY. 



Quod si cui mortalium cordi et curse sit non tantum inventis hserere, atque iis uti, sed ad ulteriora 

 penetrare ; atque non disputando adversarium, sed opere naturam vincere ; denique non belle et ])robabiliter 

 opinari, sed certo et ostensive scire; tales, tanquam veri scientiarum filii, nobis fsi videbitur) seadjungant. 

 —Novum Organum, Prcefatio. 



VOLUME THE FORTY-SIXT 



1890. 



r^N Wis 



'z-s^-yizi 



iHimiV"^^^'^'^ 



LONDON : 



LONGMANS, GREEN, AND CO. 



PARIS: FRIED. KLINCKSIECK, 11 RUE DE LILLE; F. SAW, 24 RUE HAUTEFEUILLE. 

 LEIPZIG: T.O.WEIGEL. 



SOLD ALSO AT THE APARTMENTS OF THE SOCIETY. 



MDCCCXC. 



