40 
\ih:x T. Pridkr. 
1.. sl;it(‘ west side <4 slnte (|ii;nry, Arnia<lale. 
)1. (’aidhrian slate, Veniionl (r.S. Geol. Surv. Hull. 591, p. 250). 
5. ('oiii[K)site atialvsis ef 7S siiales ( l'\ W. (‘larkti, “Data, of (JooelieniistryP 
II.H. (;eol.' HuV. 770, 1021, p. 50). 
4. Illite (fine eolioid frai-ti(ni), Oialoviriaii shale, (Jilead, Callioiiii Do., Illinois 
(I*. lO. (ii-iiii, It. A. Di'ay and VV. K. Itradlcy, “The miens in argillaceous 
M‘d inn Ills, ’ ’ Avtcr. Mm. Vol. 22, 1057, ji. 825). 
5. Analysis nf Ainiadale slate (of eol. 1) with Si()_ reduced to 50% and the 
(dher oxides reealeiilated to snni to 100, tor eoniparison with analysis of 
lilile (((d. 4). 
In this (ald(‘ the analysis of tin* iV rinada h* slate is eoiujiared with that 
<)1 a slale from Veiinonl, I'.S.A. (col. 2) whiidi it resembles very elosedy, 
and with the a\'erag'e (d ^8 analyses nl shah‘ (<'oI. 5). The main f(‘atures 
ol the anajysis ai’(‘ IIk' high silii-a, alumina and potasli, the two laittvr Ixdng 
a. ('(dh'ctioii nl tin* high sei‘i('i|.(‘ (-ntilenl. Such featun's would be eoTiimon in 
slates dei’i\-ed 1 i-<nn iliit(‘ ri<'h (dayey sedinumts (an analysis of illite is slunvn 
in (able *2, eol. 4 and is ('ompared with that of the Armadale slate from 
whi('h e.\('(‘ss silica has been removed ((-ol. 5), and although tJie potash 
cont.enl is liigii, il is quite norma! and do(‘s not indicate that tlie rocd< has 
suftered any “granitisalion.” 
(c) More types: to llu' east the slates become more 
arenac(‘ons and pass gradually iido the normal sandstones. On th(j western 
sid(^ of the (inarry, Ind.ween tlu' whitn slale and the albite epidiorile, there- 
is a, l>and ol greenish mor(‘ sandy slate, ddiis hand swings towards the ea-st 
at tlu* south {‘lid ol Ihe (piarry. This nn-k is distinctly coarser lextiin'd and 
(comparatively larg(* rounded (piarlz gi’ains ai‘e abundant — the (^nly other 
(const it iieiit ol note is a gr('('nish lirown hiotitx* which app(*ars to have 
de\(*lopcd during ('ontaet metamorphism ol this band bv tlie basi(' ijitrusive. 
S(*paration oi llu* h(*avy min(*rals yiehh'd only a IV'W miudi woiai and rounded 
/ii('ons. A| tlu* south ('lul ol tlu* (piarry this gi'(‘enisli ro('k (‘ludoses several 
rounded lioiilders ol granitic material which consist lai’g(*Iy of a graiiophyri(C 
in((‘j'grow(h oi (piart/, and acid plagioelase, T!u*se “boulders’^ appear to be 
sonu'wiial rounded and some doubt exists wheilier th(\v are boulders or 
irregular g -anopliyrie intrusion.^, as tlu'.v are lrav('rsed by nan-ow (%dnch 
wide) v(*inh*(s ot (piarlz whiidi app(‘ai' to ])ass through both tlie boulders 
and llu* (‘ludosing green sandy s('(Iim(‘nt. I incline to llu* view (hat they 
ar(* honidei’s and that llu* associated v(‘inl(‘ts aia* similar to the (piartz v(*ins 
d(*V(’lop(Ml in (lio (hirdup Series (whi('h are descri])(‘(i iiiuh'r “(|iiartz veins'^' 
I)(*1()W ) . 
(iii) ( oiitaet vtefidHorpliisni oj the ('avdep sediteoits. 
Donsi(h‘ring first the an'iuuM'ous ro(dcs (-lose to tlu* I'ontaet with the 
gi-anitie ro(-ks— (he main eonlaet metamorphie (‘ffeets have h(‘('n (he intro- 
(Inetion of (‘pidoti* and llu* (lev(*lopm(‘nt in certain narrow hands of a(-i(-ular 
(f) aetinolib* the latl('r ari* in radiating aggr(*gal('s and appear to iM'snlt 
from (he liu'i’iual nu*tamor]>iusm of a slightly eaIcar(*oiis rock hut wh(*llu'r 
this alteration is due to intrusion by (lu^ granite oi* to intrusion by the (]uartz 
(lo!(‘rit(' dyk(‘s is not ch'ar tlu* introdnetion of (he ejiidote was most likely 
efr('('(('d during the intrusion of tlu* doleritif^ rocks. 
In the slat(*s lying farther to the w(‘s( tlu*re lias he(*]i some new mimu'al 
d(*v('!opmen( : — 
(.1) The (levelopnu'nt of the kaolinic knots whi(di seems to be closely 
relat(‘d to tlu* gi’oenstoiu* intrusions. 
