ON THE CRYSTALLINE ROCKS OP ANGLESEY. Il3 



£ Red Limestone, in the same beds as above. 



I. IT. 



Residues insoluble in HC1 15-63 15-72 



ALA+Fc.,0.1 2-35 2.39 



CaO 41-88 41-93 



MgO 3-11 303 



C0 2 . 36-69 36-74 



99-66 99-81 



Percentage CaCO, 74-78 74-87 



MgC0 3 6-53 6-36 



Both the above rocks are from the Penrhoslligwy district. 



Dolomite. — From shore east of Portli Penmon. 



I. II. 



Residues insoluble in HC1 0-85 89 



Al 2 3 +Fe 2 3 2-08 2-02 



CaO 30-17 30-03 



MgO 20-84 20-86 



C0. 2 46-48 46-44 



100-42 100-29 



Percentage CaC0 3 5387 63-71 



„ MgC0 3 43-59 43*63 



This is a thick, massive bed in the Carboniferous limestone. 

 Finally, in a peat ash from Cors y Bol, Llantrisant, an extensive old 

 alluvium, the percentage of phosphoric acid has been determined: — 



I. II. 



Percentage P 2 O s 1-71 179 



And one of the well-known hornblende picrites of Llandyfrydog has 

 been examined for nickel, as there was an impression that this existed in 

 it in some quantity, but no nickel was detected. 



Mr. Hughes desires to point out that his leisure for research work 

 during the past session lias been rather small, and that the greater 

 part of his analytical work will be done in the coming summer vacation 

 — too late, that is, for the results to appear in this report. 



The Excavation of Critical Sections in the Palceozoic Rocks of Wales and 

 the West of England. — Report of the Committee, consisting of Pro- 

 fessor C. Lapworth (Chairman), Mr. G. W. Fearnsides (Secretary), 

 Dr. J. E. Marr, Professor W. W. Watts, and Mr. G. J. Williams. 



[Plate III.] 



'Ihird Report on Excavations among the Cambrian Rocks of Comley, 

 Shropshire, 1909, by E. S. Cobbold, F.G.S. 



The excavations made during 1907 and 1908 were reported upon to the 



Dublin and Winnipeg Meetings of the British Association. As the funds 



placed at my disposal by the Committee appointed in 1907 had not been 



1910. t 



