THE 



QUARTERLY JOURNAL 



GEOLOGICAL SOCIETY OF LONDON. 



EDITED BY 



THE ASSISTANT^SECRETABY OF THE GEOLOGICAL SOCIETr. 



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

 penetrate ; atque non disputando adversarium, sed opere naturam vincere ; denique non belle et probabiUter 

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

 —'Novum Organum, PrcBfatio. 



VOLUME THE FORTY-EiatlTU^ 



1892. .^V 





LONDON : 



LONGMANS, GEEEN, AND CO. 



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

 LEIPZIG: T. O.WEIGEL. 



SOLD ALSO AT THE APARTMENTS OF THE SOCIETY. 



MDCCCXCII. 



