224 



are surmounted by an overlying mass of rudely columnar trap, the 

 northern extremity of which forms the magnificent promontory of 

 Fair Head. 



Besides the hornblende schist, which is interstratified with the mica 

 slate and dips conformably with it, there are other rocks containing 

 hornblende, which appear to be imbedded in the slate, but which are 

 really intruded veins. On the sea-shore at Torr Point are two of these 

 veins, consisting of syenite and syenitic green-stone; and they may 

 be traced passing obliquely along the face of the stupendous and, for 

 the greater part, perpendicular cliff of Goodland. On the sea-shore 

 they appear so regular and conformable, both in strike and dip, to the 

 strata of mica slate, that they might be considered as integral portions 

 of it ; but on minute inspection the syenite is found to mould into the 

 rough and saw-like edges of the strata of mica-slate ; and on tracing 

 the veins as they gradually ascend the cliff, they are found to pursue 

 undulating courses, neither parallel to each other nor to the laminee 

 of the slate, in some places approaching within four feet, and in 

 others being more than 20 feet apart. To the south of the fault 

 which traverses the cliff about 150 yards from Torr Point, the veins 

 reappear at a higher level than on the north of the line of dislocation j 

 and between the two previously noticed is a third and smaller one. 

 Where first seen, this small vein is in contact with the upper surface 

 of the lower vein, from which it gradually diverges and approaches 

 the upper, but afterwards again descends towards the lower vein. 



The mass of the two larger veins consists of dark green, crystallized 

 hornblende, brownish red felspar, and occasionally quartz • and re- 

 gular transitions may be traced from syenite to greenstone. When 

 viewed at a distance they present a rudely columnar structure. The 

 centre vein contains much black hornblende, some black quartz, and 

 presents a concretionary structure, the oval-shaped masses being en- 

 veloped in a congeries of pinchbeck brown mica. A tendency to this 

 structure is observable also in the upper vein. 



Owing to the covered nature of the ground, the syenite veins of the 

 coast cannot be traced continuously to Torr Eskert, but by laying- 

 down the line of the veins of Goodland cliff on the Ordnance Map, 

 and making due allowance for their average inclination and the ele- 

 vation of the hill, Mr. Griffith entertains no doubt that the syenite in 

 the chalk of Torr Eskert is a prolongation of one of the syenite veins 

 in the slate of the cliff. 



The syenite which traverses the chalk cannot be distinguished from 

 that of the mica slate, and passes also in syenitic greenstone. At one 

 point the author had a portion of the surface soil removed, andobtained 

 the following section: 



Top. Compact chalk 5 feet 



Syenite 5 — 



Chalk, irregular bed from 9 inches to 1 foot 



Mica slate 



The lower bed of chalk contains quartz pebbles, green sand, and 

 numerous, red, siliceous grains, some of which resemble garnets. The 

 syenite presents large masses separated by chalk containing quartz- 



