196 
Mr. Weaver on the 
exposure acquires on its joints and fissures so great a variety of tints* 
becoming more particularly discoloured by a dirty yellow, brown, 
or red. In the same manner the variegated colours of the stratified 
rocks on the southern coast may be in part accounted for. 
§ 87. Ireland's Eye, (see PI. 9. No. 14.) may be considered as a 
dismembered portion of Howth. The south-eastern angle is a con- 
fused intermixed mass of clay slate and quartz rock, the former pre- 
dominating, much iron-shot, and partially decomposed. The strati- 
fication is not regular, but mostly disposed in a north-east and south- 
west direction, dipping 50° toward the south-east. But the mass 
of the island to the north, that is to say, the whole upper region and 
ridge down to the water’s edge on the north, east, and west sides, 
consist of massy quartz rock, without any appearance of stratifica- 
tion. It betrays its usual characters, which have been already 
developed. 
§ 88. In the whole expanse of the clay slate formation, the de- 
scription of which I have now concluded, I have never perceived, 
either on the western or on the eastern side of the granite chain, 
the slightest vestige of organic remains. Hence, I cannot subscribe 
to the application of the term transition , which has been bestowed 
upon some of these rocks, as well as upon the analogous tracts of 
clay slate in other parts of Ireland; conceiving as I do, the essential 
distinctions of the formations, properly to be considered as inter- 
mediate between the primary and the floetz classes, to consist not 
only in the nature of the rocks themselves, but also in the circum- 
stances of their relative position, and in their containing the remains 
of organized bodies ; and being consequently of opinion, that neither 
the mere occurrence of matter mechanically divided in the composi- 
tion of rocks, nor the curvatures or inflections which their strata 
sometimes display, entitle them to a place among the transition 
