210 



C. CALLAWAY ON THE AECH.EAN 



15. The Aech^san Geology of Anglesey. By C. Callaway, Esq., 

 M.A., D.Sc, F.G.S. With an Appendix on the Microscopic 

 Stpjjcture of some Anglesey Rocks, by Prof. T. G Bonney, 

 M.A., F.R.S., Sec.G.S. (Head January 5, 1881 J 



[Plate VIII.] 



Introduction (p. 211). 



A. Description of Areas and Sections. 



I. Menai Anticline (p. 211). 

 a. Gneissic series. 



(1) South of Pentraeth. 



(2) Mynydd Llwydiarth. 



(3) G-aerwen to Menai Bridge. 

 Slaty series. 



II. Llangefni " Syncline " (p. 213). 



a. Slaty series. 



(1) Llangristiolus slates and grits. 



(2) Llangefni conglomerates and shales. 



(3) Cerrig-Ceinwen slaty and calcareous group. 



b. Gneissic series. 



(1) Coast section from Porth jSTobla to Aberffraw Sands. 



(2) Railway-section from Ty Croes to Bodorgan. 



(3) Distribution of the subdivisions in localities to the north-east. 



III. Central Zone (p. 218). 



a. Slaty series. 



b. Gneissic series. 



(1) Bodafon Mountain. 



(2) Section between Llangwyllog and Llanerchymedd. 



(3) Area south-east of Paris Mountain. 



(4) Structure of the Zone. 



IV. Northern Area (p. 221). 



(1) Volcanic group of Paris Mountain. 



(2) Chloritic schists of Mynydd Mechell. 



(3) Llanfechell grits. 



(4) Rhosbeirio shales. 



(5) Sharply contorted group south-east of Amlwch. 



(6) Slates and limestones of Amlwch and Cemmaes. 



V. North-western Area (p. 224). 



Section from Porth y defaid to Pen bryn 'r Eglwys. 



VI. Western Area (p. 225). 



(1) The Mainland. 



(2) Holyhead district. 



(3) Bhoscolyn district. 



B. Summary of Results. 



I. Distribution of the Rocks (p. 227). 



a. Gneissic series. 



(1) Geographical. 



(2) Stratigraphical. 



b. Slaty series. 



II. Evidence of Age (p. 229). 



a. Relations to Palaeozoic groups. 



b. Relations to each other. 



c. Relations to other areas. 



(1) Caernarvonshire. (3) Shropshire. 



(2) St. David's. (4) Charnwood. 

 Conclusions (p. 232). 



Appendix (p. 232). 



