192 
Mr. Weaver on the 
Newtown and Ashford, where the beds, which at first have a south- 
eastern inclination, gradually become vertical, and then as gradually 
approach to a north-western inclination; when, the progression 
being repeated, a south-eastern inclination is resumed. But partial 
deviations of this description should not be confounded with the 
general disposition prevailing in an extensive district. I have 
already alluded to their probable proximate cause, (§ 67.) 
§ 86. After the full consideration which we have given to these 
rocks, the peninsula of Howth may be disposed of in few words ; 
(see Plate 8. No. 9. and 9. No. 11. and 12.) It consists of re- 
peated alternations of clay slate and quartz rock, both pure and 
intermixed with each other, so as sometimes to acquire the character 
of greywacke. There are not less than twelve alternations of this 
kind on the large scale, and the smaller are innumerable. In the 
larger, the quartz rock itself is in mass, and exhibits no distinct 
signs of a division into strata. 
On the northern brow of Howth, just above the town, the 
beds range 40° east of north and west of south, and dip 45° 
to 50° toward the south-east ; but to the east of the town they 
range 15 north of east and south of west, and dip 30® to 45° 
toward the east of south. In fact, we have entered at this place 
upon a great curve in the beds, which may be traced toward 
the Head-land, gradually trending more and more toward the 
south of east, until the range acquired remains nearly stationary, 
being 40° east of south and west of north, with a dip toward the 
south-west ; as may be observed in the cliffs on the eastern and 
southern sides of the peninsula. The lowest beds on the north 
side are the flattest, and in ascending the hill the angle of their 
elevation gradually increases, rising to 60°, and subsequently to 70°, 
as may be seen along the eastern coast ; while upon the southern, 
