388 John 8. Flett—Ortkite in Scottish Bocks. 



Milne-Edwards, of no less tlian four thousand facets." (See Alex. 

 Acrassiz, "Three Cruises of the 'Blake,'" vol. ii, 1888, pp. 49-51, 

 and figure.) 



Although these recently discovei'ed living deep-sea Isopods exceed 

 it very considerably in size, I think we may justly conclude that the 

 fossil Cydosphceroma was in all probability also a deep-water form. 



In comparing the fossil SphEeromid with various living Isopods, 

 one cannot fail to be struck with the resemblance it offers in the 

 telson to the pointed and keeled terminal plate of the pleon in 

 jEga monophthalma and in Idotea, particularly in Idotea entomon ; 

 but there the resemblance ceases, for in other respects this form 

 is an undoubted Sphseromid. One need not be surprised, however, 

 to find in a Mesozoic form evidence of more generalized Isopod 

 characters than now prevail in the family of the Sphseromidas, 

 to which we are led to refer it. One is only astonished to find 

 an Isopod resembling so nearly our existing Sphseromids, but dating 

 back in time to the Purbeck and the Great Oolite rocks. 



EXPLANATION OF PLATE XIV. 



Fig. 1. CpcJosphcsroma trilobatmn, H.WooAw., 1890. Great Oolite : Northampton. 



Drawn of the uatnral size. The original specimen preserved in the British 



Museum (Natural History). Jesson Collection. 

 Fig. 2. Cychsphm-oma trilohatum, H. Woodw., 1898. From the Purheck Beds 



near Aylesbury; discovered by E. J. Garwood, Esq., M.A., F.G.S.,hy whom 



the original has been presented to the British Museum (Natiu'al History). 



Drawn of the natiu-al size. 

 Fig. 3. Cassidina emarginata, Guerin. Eecent: Kerguelen Island. Twice 



natural size. From a specimen in the British Museum. 

 Fig. 4. Cassidina maculata, Studer. Eecent : Kerguelen Island. Copied from 



Studer's figure. 

 Fig. 5. Sphceioma curium, Leach. Coast of Devonshire. Six times natural size. 



From a specimen in the British Museum. 

 Fig. 6. Spharoma gigas. Kerguelen Island. Drawn twice natural size. From 



a specimen in the British "Museum. 



IL — On Scottish Eocks containing Orthite. 



By John S. Flett, B.Sc, M.B., CM. ; 



Assistant in Geology, University of Edinburgh. 



FEOM America and from many different localities on the continent 

 of Europe the occurrence of Orthite or Allanite as an accessory 

 mineral in crystalline rocks of different kinds has been frequently 

 described. But so far it does not seem that its occurrence in Great 

 Britain has been recognized, or at any rate I have failed to find any 

 mention of it. Quite recently two instances of Scottish orthite- 

 bearing rocks have come under my notice Avhicli I wish to describe 

 briefly in the present communication. Both are in acid holo- 

 crystalline rocks — granites and gneisses — and in both it is associated 

 with the closely allied mineral epidote, as is usually the case. For 

 specimens of the granite of Fell Hill I am indebted to Mr. James 

 More, jun., M.Inst.C.E., Edinburgh, who sent sections of this rock 

 for microscopic examination to Professor James Geikie, Edinburgh 

 University. Although only two in number, the sections contain at 



