Dr. F. A. Bather — Notes on Yunnan Cysiidea. 507 



3. The 

 SiOa 

 TiOa 

 AI2O3 

 FesOa 

 FeO 

 MnO 

 (NiCo)O 

 BaO 

 SrO 

 CaO 

 MgO 

 K2O 

 Na2 

 LisO 

 H2O below 100° C. 

 H2O above 100° C. 

 P2O5 

 FeS2 

 CO2 

 F . 

 CI . 



Glan-oee Type. 



50-76 

 2-10 



16-01 

 0-86 

 6-90 

 0-11 

 none 

 none 



traces 

 3-55 

 8-02 

 0-81 

 3-78 



traces ? 

 0-41 

 5-83 

 0-26 

 0-41 

 0-61 

 none 



traces 



Total . . . 99-92 



In conclusion, I wish to express my indebtedness to Miss 

 Chamberlain, who placed her notes and maps at ray disposal, to 

 Dr. Morley Davies, who identified the fossils, and to Professor Watts, 

 who looked through the proofs and made valuable suggestions. 



EXPLANATION OF PLATES XVIII AND XIX. 

 Plate XVIII. 

 Fig. 1. — Augite moulded on felspar, N. of Llanwefr Pool. (Diabase.) x 16. 

 ,, 2. — Ilmenite moulded on felspar and augite, Graig-fawr. (Diabase.) 



X 35. 

 ,, 3.— Olivine basalt, E. of Little Wern. x 27. 

 ,, 4. — Pseudomorph after olivine, S.W. of Llanwefr Pool. (Glan-oer type.) 



X 31. 

 ,, 5. — Ophitic structure, Glan-oer. (Glan-oer type.) x 34. 



Plate XIX. 



Figs. 1-3. — Specimens of diabase intruded into Llandovery Limestone from 



Eiver Edw, S. of Pye Corner, Eadnorshire. x 1| nat. size. 



V. — jS'oxes on Yunnan Ctstidea. I. Sinocystis and Ovoctstis. 



By F. A. Bather, D.Sc, F.E.S. 



(Published by permission of the Trustees of the British Museum.) 



BEFORE returning to Calcutta the specimens described in his 

 memoir " Ordovician and Silurian Fossils from Yun-nan" 

 (1917, Palaeont. Ind., n.s., vol. YI, Mem, 3), Dr. F. R. Cowper 

 Heed very kindly lent to the Geological Department of the British 

 Museum the figured cystids, in order that plaster casts of them 

 might be made and kept there for reference. This was done, and 

 a set of the casts was also furnished by the Department to the 

 Sedgwick Museum, Cambridge. While preparing the specimens for 

 the moulder, I had the opportunity of studying them with some 



