Ttik Contact Between tiie Ghanitic I^ocks and the Cardtp Series 
AT AliilADAEK. 
Minor structures (other thiui the g'raded be<ldirig* seen in several i>laces 
on the Bedfordale Road) observed in the Cardup sediuuaits were visible 
only in the slate <iaari'y as other exposures are rather poorly develo]>ed. 
A detailed survey of the (juarry was niad(‘. tor dragfolding', minor faulting 
and fracture cleavage and the results are shown in (igiire 2 (plan and set*- 
tion of the slate quarry), d'he drag-folds indi('ate that the beds to the west 
have moved up and over the beds to the east, i.e., that the slates in this 
quarry form the westei’u liiidi of a normal anticline. A close examination 
across the black carbonaci'ous slate band at the south end sliows that the 
dragfolds are directed in the same direc'tiou right throughout tiu* band thus 
precluding the possibility of isoclinal folding in tliese rocks. All of the 
dragfolds observed pitch to the smith at 10° to 15°. The bedding planes 
of the dragfolded slates show a, distinct set of sli<'kensides (Ilarnisch) which 
strike K. to W. normal to the axes of the dragfolds. Tests mad** of the 
roughness of the b(?dding surface in this direction indicate that the beds to 
the west have moved up and over the beds to the east. 
The fracture cleavage is rath(*v poorly developed in these rocks but 
where present is (-onstant in strike (])arallel to the bedding) and di]) (almost 
vertical) throughout- the quarry. In the northern wall of the (piarry there 
are a number of small faults de\eloped which ai'e generally ])arallel to the 
fracture clea-vage and along which movements u]) to 6 inches have Ixm'U 
observed. AH of these small faults (which an^ either vertical or di]) very 
steej'jly to the west) are of nnersed (diaracter and indicate uplhrusting fi’om 
the west (as deduced from the curvature, due to dragging, of the bedding 
planes in the vicinity of th*' faults). 
It will be seen that all of these minor structures ar*^ *dosely related and 
almost certainly developed by the sanu’ movenu'iit, viz., a moviummt causing 
the westeiTi beds to be moved uj) and over the beds to the east. Tlu'ri* are 
therefore two possible interju'etations p*>ssible for these minor strnctma's: — 
(i) Tliat these beds form tin* westcwn limi) of an anticlim* which ])it('h(‘S 
flatly To tlu* south 
or 
(ii) That there has been upthrustiug from the west, the sediments hav- 
ing been upthrust over the graniti*' gneisses lying to the east. 
Considering the striudural IVatures ol’ the Cardup sedinu'iits in con- 
junctioii with the structures in tlu* band of tint* grained granitic gneisses 
adjoining tlieni lo tin* east we s('e that they ap|)ea.r to bt* to some extent 
complementary, the gneisst's forming tlu^ east Hmh ot an aidicliiu', tlu* s(*di- 
ments forming tlu* wt'st limb ot flu* same anticline. Foi'inan (1057, p. xxiv.) 
considi*rs tliai tlu* gn(‘iss('s may I'epresent jiorlions of tlu* (knrdiip sediments 
which iun** sudei’ed gi'anitisation and it has I>e(*n sugg<‘sted to me (in dis- 
cussions with Mr. n. A. Fllis) that in the Armadale Ar(‘a tlu* gneiss<*s and 
sediments form part, of a singit* siriictural unit (an an1i(‘linal told ) wtiich 
at the tinu* of folding *'onsist**d (*ntirely of sediuu'iitary ro(d<s ot tlu* (Cardup 
Series, hut which has siuc** siitfered partial gi'anitisation, all of tlu* rocks 
lying to the east ot‘ the axial |)lane of this anticline having h**eii graiiilised 
and those to the west remaining unattected by the granidsing solutions which 
came from the east. Detailed held ma])])ing, espt'cially in coinu*clion with 
the field relations ot tlu* (piart-z ^'*‘ins, apjiears to indi<'at(‘ that the giu'isses 
antedate the s*‘dimen(s, whereas the granitisation Itu'ory suggested by 
Forman (loc. cit.) I'cquires tliat the (kirdu]) si*dim<‘nts should he older than 
