THE 



QUARTERLY JOURNAL 



OF THE 



GEOLOGICAL SOCIETY OF LONDON. 



EDITED BY 



THE ASSISTANT-SECRETARY OF THE GEOLOGICAL SOCIETY. 



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

 penetrare; atque non disputando adversarium, sed opere naturam vincere ; denique non belle et probabiliter 

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

 —Novum Organum, Prcefa<.io. 



VOLUME THE FORTY-THIRD. 



1887. 



LONDON: 



LONGMANS, GREEN, AND CO. 



PARIS: FRIED. KLINCKSIECK, 11 RUE DE LILLE; P. SAVY, 24 RUE HAUTEFEUILE. 



LEIPZIG: T.O.WEIGEL. 



SOLD ALSO AT THE APARTMENTS OF THE SOCIETY. 



MDCCCLXXXYI1. 



