546 PROF. T. R. JONES ON SOME DEVONIAN AND 



§ IT. From France {Brittany). 



Nos. contd. Sil. sp. 



36. 23. Beyrickia GuilUeri, Tromelin, PI. XXI. fig. 2. Lower 



Silurian. 



§ I. Of the Silurian Ostracoda, from North America, additional 

 to those described and figured in the Eebruary ]N"umber of the 

 * Quart. Journ. Geol. Soc.,' we have nine species collected by Dr. 

 G. J. Hinde in Anticosti. Of these, five belong to the Divisions 

 3, 2, & 1 of Billings's four Divisions of his '■' Anticosti Group,"* and 

 four to the lowest Division there, which he termed the " Hudson- 

 river Group." This last Division is equivalent to Groups A and B 

 of the Geological Survey of Canada (Ileports 1853-56, and 1863), 

 and is now regarded. Dr. Hinde informs me, as equivalent to the 

 " Cincinnati Group " t. 



Group C is equal to Billings's Division 1 of the " Anticosti Group," 

 and was placed by him doubtfully at the base of the Middle Silurian 

 there, but is now regarded by Dr. Hinde as being more probably 

 Lower Silurian. GroupD = Div. 2, Group E = Div. 3, and Group F 

 = Div. 4 of the Anticosti Group, were characterized by what Mr. 

 Billings regarded as Middle-Silurian fossils, but the term " Middle 

 Silurian " appears to be almost obsolete with American geologists. 

 Mr. Billings included the " Medina, Clinton, Niagara, and Guelph '' 

 Formations of New-York State and Western Canada in the " Middle- 

 Silurian" series. 



The genera to which these nine species belong are already in- 

 cluded in the Table at p. 2 of the previous memoir (February 1890) : 

 but all the species are new. 



§ I. From Anticosti^ Canada. 

 II. Beyrichia, M'Coy. (See also pages 236-238.) 



14. Beyrichia DiFPissA, sp. nov. (PI. XXI. fig. 7.) 



Length 1*5 mm. ; height 1 mm. 



A rather narrow-lobed Beyrichia, not far removed from some 

 varieties of B. Kloedeni, but having its anterior lobe long, narrow, 

 oblique, furrowtKi, and, as it were, split longitudinally for the 

 greater part of its length. Hence the proposed name diffissa. The 

 middle and hinder lobes unite below ; and the latter is broad and 

 faintly punctate. The upper ends of the split lobe are broken in 

 the specimen. 



From the Division 3 of the Anticosti Group, Jupiter River, 

 Anticosti. Attached to an Atrypa. Coll. Dr. G. J. Hinde, F.G.S. 



* • Geol. Surv. Canada : Catalogues of the Silurian Fossils of the Island of 

 Anticosti; 18f)6. 



t In the February No. of the Q. J. G. S., at p. 28, 8th line from the bottom, 

 Div. G should hr. Div. A. At p. 27, 3rd line from the bottom, for fig. 17 read 

 fis[. 12. 



