IO THE JOURNAL OF GEOLOGY. 
In this particular case, and in others like it, the biotite seems to 
be original, at any rate there is no evidence that it is secondary. 
Chlorite is another of the unessential components of the 
granulitic rocks. It is however always in such small quantity 
that its effect upon the general aspect of these rocks is not 
marked. 
The analyses of two specimens of the hypersthenic rocks 
follow: 
I Il. 
SLO Fh Pere ees PEA iT RIAN Lone HE ae eee 46.96 49.56 
SK OFS rsh San i CN ees ena ot eae mee SS Cha ERIE iG Poe .62 48 
PSUS O ahchacccerstatetenaehasis sealer a uses ace eas Mies atsdan cium ener ert IN 14.13 17.81 
CCS ENO Aen ee ee ar enter es ie ti reel ei yeh UO gett eye neg tr. 
THE SO Sei eeatentn sila tue te ales ey EA LaAR DAtra RO Hebi .76 25716 
Ja XO PS See Ue ers ee RR RCs Perey ea ce apni ale eR eee tee cute 14.95 9.48 
INGO ear sireporieitd eiGave ais hus A aie etarG GIoIetaa ain oo ERaRSe .06 
IN Bak Oise raireet pte tai auet Gora Siac yey Nese RI eae unpre Bl 508} 06 
CaO aa een Shes respite ep eT ge ee Rea ene eee ot er 2), BD) 9.70 
MESO) a icing siete eee dye ap en eac titi oie ec Dre A AON ge ge 15.97 5-93 
TOE OG erecta she eae anc eepiarer eee aoa ane ee ee les taal ea 1.68 
UN test ® eres tory aura aire laacnelbe MRO Mr amr mung aien tia aA olin AS 2.87 
Fill Ol at elo Gir \acieusnne os Meee maleate teetels Lid peeeiradie eaiayeeay ae .07 5 
TAS Ora bove wlOlS in sys ste y ae eteth cei aegis lee i alent 1.26 “5 
LEN OF seach bain au OR nr on Uy UUM SR eal eee .03 .67 
FINO Galles) SN e152 SC Nala cance te atone ene arr 100.09 99.82 
SP Grasse neers ney eh aes edd cr nae een eee Me esa ORE BElog 2.967 
I. Granulitic hypersthene-gabbro. Very rich in hypersthene 
and biotite and poor in feldspar. Much of the latter is unstri- 
ated. =) Analyzed by Ire El INeestokes. = INo.70 36: 
II. Granulitic diallage-hypersthene-gabbro. Diallage much 
more abundant than hypersthene. No mica. Most of the feld- 
spar striated. Analyzed by W. H. Melville. No. 8879. 
Nallagic Varieties —The great majority of the granulitic gab- 
bros contain neither olivine nor hypersthene. These rocks con- 
sist essentially of diallage and plagioclase, or of these minerals 
with biotite and hornblende. The varieties without the last two 
named minerals are not as common as those containing them. 
Indeed, only three sections of diallage rocks free from biotite 
