534 PRO¥. T. K. JONES ON SOME DEVONIAN AND 



32. On some Devonian and Silurian Ostracoda from North 

 America, Ekance, and the Bosphorus. By Prof. T. Rupert 

 Jones, F.E.S., F.G.S. (Read May 21, 1890.) 



[Plates* XX. k XXL] 



Contents. 



§ I. Devonian Species, from Xorth America and the Bosphorus. 

 § I. From Clarke Co., Indiana. 

 I II. From Thedford, Ontario, Canada ; and Eighteen-mile Creek, 



Lake Erie, New-York State. 

 § III. From the Bosphorus. 



§ XL Silurian Species. 



§ I. From Anticosti, Canada. 



§ II. Silurian Species from Dundas, Ontario, Canada. 



§ III. Silurian Species from Canada, Coll. G-eological Survey of 

 Canada. 



§ IV. A Lower-Silurian Bcyrichia (from Brittany), named and dis- 

 cussed by M. G-. de Tromelin some years ago, but not hitherto 

 figured. 



§ I. Devonian Species. 



§ I. As stated at page 14 of the Quart. Journ. Geol. Soc. for 

 February last, Mr. J. M. Clarke, of Albany, jST. Y., sent me some 

 Devonian Ostracoda, collected by him in Ontario Co., N. Y., and 

 some from Clarke Co., Indiana. These are now illustrated and 

 described herewith. 



1. The first-mentioned occur in the buff-coloured, earthy portion 

 of a decomposing siliceous rock, known as " the Chert of the Corui- 

 ferous Limestone," and cavernous with casts (internal and external) 

 of Polyzoa, Ostracoda, remains of Trilobites, and other organisms, 

 comprising some interesting specimens of Beyrichia and allied 

 genera. There are six species, and these are illustrated in PI. XX. 

 figs. 4, 9-13, and PI. XXI. fig. 1. 



2. Two species, collected also by Mr. J. M. Clarke, from the 

 Hamilton Group, Clarke Co., Indiana, U. S., PI. XX. figs. 6 & 7. 



§11. Among the additional Ostracoda, collected by Dr. Hinde, 

 F.Gr.S., as mentioned at page 28, Feb. Xo., Q. J. CI. S., are some Devo- 

 nian Ostracoda from the Hamilton Group at Thedford, Ontario, 

 Canada, and from the same formation at Eighteen-mile Creek, Lake 

 Erie, N.Y. Four of these, being new species, are here described 

 and figured (PI. XX. figs. 5 & 8 ; and woodcuts, figs. 1 & 2). 



Note. — The genera BolUa, 31oorea, Octonaria, EurychiUna., and 

 UlricJda are hereby added to the list of " Hamilton " fossils. 



* These Plates have been drawn with the aid of a Grant from the Eoyal 

 Society. 



