




316 Journal of the Asiatic Society of Bengal. [September, 1912. 
extraordinary difference between the mode and norm of 
kodurite led me to investigate the cause, in other words to 
under considerable pressur 
From this I was led le nga’ various other or 
erous rocks, such as eclogite, 
arrive at the snohbinoe that the akeoes 
one Sega in the earth’s crust the more abundant penta oie 
Garnetiferous rocks. | 
edicabhite of pyroxene, olivine, and an Seen - rearrange 
gore Mee as the | enser molecule ge nclusion 
mine 
with anorthite, have rearranged themselves as far as able 
into garnets, for thereby the maximum reduction in volume 
and absorption of heat is effected. 
At present, atts sg regard the plutonic rocks, 
as granite and gabbro, as the most 
pales Pntene po paaeasres known Flee.” But, under 
the effects of enormous pressures, the granites should become 
_ garnetiferous and the gabbros be converted into eclogites, and 
the conclusion seems inevitably to follow that beneath the 
rocks now known as plutonic there must be a zone of cba 
ferous rocks extending downwards in a plastic-solid form as 
as the presumed metallic core of the earth.'! For this zone, 
Ket Po better term suggest itself, I propose the name infra- 
pluton 
The characteristic minerals of the infra-plutonic zone will 
be those that occupy the least volume. 


a age ibly that the shell between the 
garnetifero 
Esco pom eg ied a to the siderolites Spa ‘meteor- 
s tecautly from garne 
pewsdin of iron, aluminium, ona chromi = St veerreuys 
