THE 



QUARTERLY JOURNAL 



OF THE 



GEOLOGICAL SOCIETY OF LONDON. 



EDITED BY 



THE ASSISTANT-SECRETARY OF THE GEOLOGICAL SOCIETY. 



Quod si cui mortaliutn 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 probabiliter 

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

 — Novum Organum, Prcefatio. 



VOLUME THE THIRTY-FIRST. 



1875. 



LONDON : 



LONGMANS, GREEN, READER, AND DYER. 



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

 LEIPZIG: T. O.WEIGEL. 



SOLD ALSO AT THE APARTMENTS OF THE SOCIETY. 



MDCCCLXXV. 



