THE SUDBURY LACCOLITHIC*SHEET 775 
greenstone, often with “pillow structure” and amygdaloidal phases, 
suggesting surface lava flows, which seems to have been an early 
eruption from the hearth of the nickel-bearing rock. It is, however, 
far more basic, containing no quartz nor micropegmatite. It is often 
quite fresh and in thin sections is found to consist of hypersthene or 
enstatite, a monoclinic pyroxene, plagioclase (bytownite), and magne- 
tite in small equidimensional grains or imperfect crystals. Here 
again the monoclinic pyroxene is often pleochroic, and all varieties 
occur linking the monoclinic to the orthorhombic form. The two 
pyroxenes make up, as a rule, more than half the section, and the 
magnetite perhaps a twentieth, the rest consisting of short, stout 
crystals of plagioclase, with two or only a few twin lamellae. 
- An analysis by Mr. J. A. Horton shows the following results: 
SIOas see ens ies Pee ea atom eget nis GAO? 00 
On tree Mee Gini et ne Se os Wer ene eS TAOS 
Hes Oe wince te Neto Merce ee crane ee ease <1 OO 
HeO a widht i iiat oti sae a cauan ei ler ean abate. E21 SO 
IVT Ope ec i ake aioe ilneaee Lat N ar acacA ere et sate 
MG OR Gc. (Salt aes eae eee eS LOTS 
CaO rn i a eae eR ON eee ee LORD 
ING Os Se dn Oe ea, Go cae ea .98 
iO ee ek eines Stee arn utr Reem 19 
MIO ae esac eitke Bete tener eee seus Kanan Ste aS 
IMOIStUTe Baye ear easly AL oc .08 
Sulphuta satiety et rere act as : .12 
AO tale 0 shat eee eee Whe 99.97 
Spe Clie Ora VAL Ye Goh pe ese hes tae ag 
This corresponds normally to the following mineral composition: 
IBVtO WRITES ius yl Soe ae ee mee Ree 2e6 
DIO PSIde ee Sy vey eee, ae cee tae ae 2.9 
Ey PerSthene Marty yar) We ee 2070 
Olivine Oe Ae at eP oee le cect Seg eet, Coma eRn i Ciao Al 
ditanicuron Ores) hae. 2) oe ee ACO 
PAPa tite int eee he geet Les ee eee - 34 
IY EICE tees tae e ayetv etl ae aa” a et ae 327, 
It is a percalcic rock of the order Gallare, class Salfemane, sub- 
class Salfemone, and may be named Kedebekase. 
