302 



BASALT. 



into which this defect does not intrude ; and man 

 persons have doubtless visited Staffa without disco 

 vering it. Although the columns have a general ai 

 of straightness and parallelism, no one is perfectl 

 straight or regular ; in this respect they fall far shor 

 of the Giant's Causeway. Very often they have n 

 joints ; sometimes one or more may be seen in a long 

 column ; while, in other places, they are not onl 

 divided into numerous parts, but the angles of con 

 tact are notched. They are sometimes also split b; 

 oblique fissures, which detract much from the regu 

 larity of their aspect. These joints are very abun 

 dant in the columns that form the interior sides o 

 the Great Cave, to which, indeed, they are chiefly 

 limited ; and it is evident that the action of the sea, 

 by undermining these jointed columns, has thus pro- 

 duced the excavation : as a continuation of the same 

 process may hereafter increase its dimensions. The 

 average diameter is about two feet ; but they some- 

 times attain to four. Hexagonal and pentagona 

 forms are predominant ; but they are intermixed with 

 figures of three, four, and more sides, extending 

 even as far as to eight or nine, but rarely reaching 

 ten. It is with the morning sun only that the great 

 face of Staffacan be seen to perfection. As the general 

 surface is undulating and uneven, great masses of 

 light or shadow are thus produced, so as to relieve 

 that, which, in a direct light, appears a flat insipid mass 

 of straight wall. These breadths are further varied 

 by secondary shadows and reflections arising from 

 smaller irregularities ; while the partial clustering of 

 the columns produce a number of subsidiary groups, 

 which are not only highly beautiful, both in them- 

 selves and as they combine with and melt into the 

 larger masses, but which entirely remove that dry- 

 ness and formality which is produced by the inces- 

 sant repetition of vertical lines and equal members. 



The Cormorant's or M'Kinnon's cave, though little 

 visited, in consequence of the frauds and indolence of 

 the boatmen, is easy of access, and terminates in a 

 gravelly beach, where a boat may be drawn up. The 

 broad black shadow, produced by the great size of the 

 aperture, gives a very powerful effect to all those 

 views of the point of the island into which it enters ; 

 and is no less effective on land, by relieving the minute 

 ornaments of the columns that cover it. The height 

 of the entrance is fifty feet, and the breadth forty-eight ; 

 the interior dimensions being nearly the same to the 

 end, and the length 224 feet. As it is excavated in 

 the lowest stratum, the walls and the ceiling are with- 

 out ornament ; yet it is striking from the regularity 

 .and simplicity of its form. But the superior part of 

 'the front consists of a complicated range of columns, 

 hollowed into a concave recess above the opening ; 

 the upper part of this colonnade overhanging the 

 concavity, and forming a sort of geometric ceiling ; 

 while the inferior part is thrown into a kind of 

 secondary mass of broad but ornamental shadow, 

 which conduces much to the general effect of the 

 whole. The Boat Cave is accessible only by sea. 

 It is a long opening, resembling the gallery of a 

 mine, excavated in the lowest rude stratum ; its 

 height being about sixteen feet, its breadth twelve, 

 and its depth about 150 feet. Upwards the columns 

 overhang it, so as to produce a shadow, which adds 

 much to the effect ; while they retire in a concave 

 sweep, which is also overhung by the upper mass of 

 cliff, thus producing a breadth of shade, finely soften- 

 ing into a full lierht by a succession of smaller shadows 



and reflection?, arising from the irregular groupings 



of .the columns. The upper part of this recess, 

 catching a stronger shadow, adds much to the com- 

 position ; while the eye of the picture is found in 

 the intense darkness of the aperture beneath, which 

 gives tone to the whole. 



The Great Cave is deficient in that symmetry of 

 position with respect to the face of the island which 

 conduces so much to the effect of the Boat Cave. 

 The outline of the aperture, perpendicular at the 

 sides, and terminating in a contracted arch, is pleasiri"- 

 and elegant. The height, from the top of the arch to 

 that of the cliff above, is thirty feet ; and, from the 

 former to the surface of the water at mean tide, sixty- 

 six feet. The pillars by which it is bounded on the 

 western side, are thirty-six feet high ; while, at the 

 eastern, they are only eighteen, though their upper 

 ends are nearly in the same line. This difference 

 arises from the height of the broken columns which 

 here form the causeway ; a feature which conduces 

 so much to the picturesque effect of the whole, by 

 affording a solid mass of dark foreground. Towards 

 the west the height of the columns gradually increases 

 as they recede from the cave, but their extreme alti- 

 tude is only fifty-four feet, even at low water. The 

 breadth of this cave at the entrance is forty-two feet, 

 as nearly as that can be ascertained, where there 

 is no very precise point to measure from. This 

 continues to within a small distance from the inner 

 extremity, when it is reduced to twenty-two ; and the 

 total length is 227 feet. The finest views here are 

 obtained from the end of the causeway, at low water. 

 When the tide is full, it is impossible to comprehend 

 ;he whole conveniently by the eye. From this 

 position also the front forms a solid mass of a very 

 symmetrical form ; supporting, by the breadth of its 

 surface, the vacant shadow of the cave itself. Here 

 also, that intricate play of light, shadow, and reflection, 

 which is produced by the broken columns retiring in 

 ranges gradually diminishing, is distinctly seen; while 

 he causeway itself forms a foreground no less im- 

 >ortant than it is rendered beautiful by the inequali- 

 ies and the groupings of the broken columns. Other 

 dews of the opening of this cave, scarcely less pic- 

 uresque, may be procured from the western smaller 

 :auseway; nor indeed, without bestowing much time 

 ind study on this spot, is it possible to acquire or 

 :onvey any notion of the grandeur and variety which 

 t contains. 



The opposite points of Scotland and Ireland on 

 he Antrim coast correspond exactly in geological 

 tructure. Of the basaltic group of hills in Ireland, 

 Cnocklead, in the northern extremity of the eastern 

 hain, offers the highest summit, rising 1820 feet above 

 he level of the sea ; but its basis is occupied to the 

 eight of 500 feet by primitive rocks, leaving 1320 

 eet for the thickness of the overlying strata. Divis 

 lill, near the southern extremity of the chain, is 

 'holly composed of these strata, and attains an eleva- 

 on of 1475 feet above the level of the sea. Cragnash- 

 ack, at the southern extremity of the western chain, 

 as a height of 1864 feet. The basaltic covering seems 

 o acquire its greatest thickness on the north, where 

 ic basaltic cap of Benyavenagh, the most northern 

 ummit of the western chain, measures more than 900 

 eet. The average depth of the basaltic superstructure 

 nay be safely estimated at 545 feet, and its superficial 

 xtent at the prodigious area of 800 square miles. 



The Giant's Causeway consists of three piers or 



