1922.] &fi0Ld£Y OF ALBEKNilT. l3o 



Lying in situ on the sill, at the time of deposit a shallow 

 sea floor, is the south-eastern patch of grit, an outlier. 



At the junction of granite and porphyry on the south 

 coast, evidence of faulting is suggested, the stream marking 

 the fault line. At the Tourgis J?ort, while inland the por- 

 phyry occurs as a mass, the rocks at the point show only a 

 kind of dyke, twenty feet wide, running N.E.-S.W. which 

 may be the western end of the Clonque dyke. At Tourgis 

 Point the dyke runs through diorite and the differentiation 

 series. 



Along the south coast and on both sides of Telegraph 

 Bay, the higher cliffs show porphyry and the lower crags con- 

 sist of granite, with quartz 1/6 inch in diameter, pale felspars 

 1/8 incii, and in less quantity biotite i/io inch, and horn- 

 blende i/io to 1/30 inch. Aplite veins are seen to invade 

 this rock, so the question of succession again becomes unset- 

 tled. 



Below the south-eastern grits the porphyry is seen pre- 

 senting a weathered and nodular surface. It is met at 

 both extremities of this patch of grits. 



At the southern end it grades towards a micro-granite. 

 The quartz is 1/3 inch, felspar 1/3 inch and the ferro-magne- 

 sian minerals are almost absent. From this point to Tele- 

 graph Bay and Trois Vaux, are repeated indications that 

 some relation exists between granite and porphyry. In Tele- 

 graph Bay is quartz-diorite, diorite, and dolerite, invaded by 

 aplite. To the north, separated by faulting, is granite- 

 porphyry. There are at least fifty almost horizontal aplite 

 bands in the Bay. They widen at the top. A fault line, 

 thirty feet wide, separates porphyry from the differentiation 

 series. The line runs S.E.-N.W. and is met again at Trois 

 Vaux. Both diorite and aplite develop gneissose structure; 

 most of the diorite contains quartz. Where porphyry crosses 

 aplite bands a yellow contact zone is given. Flow structure, 

 already alluded to, occurs between Telegraph Bay and Nash 

 Bay, clipping at 80 to S.S.W. 



West of Telegraph Bay the outlying rocks are of diorite 

 with aplite bands. 



Landward is the porphyry, always on the higher ground, 

 three hundred yards inland from the coastguard station. 

 The bluffs here are of tonalite but fragments of porphyry 

 are there. 



At Trois Vaux again the porphyry is inland, in this case 

 one hundred feet from the cliffs, but the latter are of quartz- 

 diorite. The faulting, as a Telegraph Bay, is seen in the 

 direction N.W.-S.E. At Clonque Fort the rock is quartz- 

 diorite with aplite bands. The cliffs overlooking Clonque 



