C^LAKKK AND Wll>DIA j\l S. — Ocolofllj of DurUllfJ Ii(UI(/e. 
171 
smalUu’ size ol: the socuml o'eiK'ratioii of t-rystals wiiicli form the 
matrix of the ].)urj)liyritir oraiiitcs, 
Tlie ri'sidual ultra-a<-i(! li(|iiors fi-oni tlio (■rystallisini>' marina 
were tiiea forced into the solidWuMl, or ])artly solidified, o'raiiito 
to form the series of a.-id and iilti‘a-a(d<l intrusions, tiie t('xtnn‘ 
of Avhieii is more or less eontinnons with tlie surrounding' eoiintry. 
Some of the ajditie oranite was involved in tlu> movemeiiTs 
ami re<-eiv(‘(l a g'ueissie structure. Tlie other acid and idtra-acid 
intrusions were injected after the tlowino- of the j>'ranite ceased. 
The tine ^'rained biotitic si'^'ri'gatioiis may perhaps ]-ei)r(‘s(Mit 
portions of a derivi'd maj>'ina, la'snltin^' from the ^'ravitationai se.i>'- 
reoation of the earliest forimnl minerals jiroduced in the first 
stage of crystallisation of the magma. 
C. Basic Rocks. 
1. Gcnrral jirld-occu rrciicc and /a /ro/of/j/.— The granite is in- 
vaded by a network of basic dyki's referable to the e])idiorite 
group. 
Th(‘ accompanying maps sho\v that tin' size and dis])osition oi 
these dykes in the Darlington and JJoloystone areas, an' similar. 
Dm. 
I’rook 
o _],]pPliorite dvke in contact with granite in (Ireenmmint 
near western edge of Darlington Area. White-barked enen- 
lyjtts on the dyke visible in background. 
