LOWER PALHOZOIC ROCKS OF ANGLESEY. — 577 
Paleozoic groups, 1 was unable to use the fact, though I more 
than suspected that the “Carboniferous” hypothesis could not be 
sustained. During visits made to Anglesey in subsequent years, 
I paid special attention to this locality, and procured additional 
information of peculiar interest. JI found, within a quarter of an 
acre, the outcrops of three rock-systems—Gneissic, Pebidian, and 
Fig. 7.— Plan of Tywyn Ridge. 
(Scale, about one inch to fifty yards.) 
W.N.W. te ae e E.S.E. 
Section 
(fiz..8), > 
Section 
(fig. 9). 
Fig. 9.—Section at Tywyn. Southern Ridge. 
(Seale of fig. 8.) 
For explanation see Fig. 4. 
Paleozoic, with proof of succession in the order here given. See 
plan (fig. 7) and sections (figs. 8, 9). 
In the middle of the northern section (fig. 8) projects a 
ridge (a) of granitoid rock (No. 110, p. 583), six feet wide and less 
than one hundred feet in length, striking nearly south-south-west. 
