M. H. 



THE 



QUARTERLY JOURNAL 



GEOLOGICAL SOCIETY OF LONDON. 



EDITED BY 



THE ASSISTANT-SECRETARY 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 probabiliter 

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

 — Novum Organum, Prts/atio, 



VOLUME THE TWENTY-SEVENTH. 



- 1871. 



PART THE FIRST. 

 PROCEEDINGS OF THE GEOLOGICAL feOCIETY. 





LONDON 



LONGMANS, GREEN, READER, AND DYER. 



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

 LEIPZIG: T. O.WEIGEL. 



SOLD ALSO AT THE APAHTMENTS OP THE SOCIETY. 



MBCCCLXXI. 



