[Proc. Eoy. Soc. Victoria, 22 (N.S.), Pt. I., 1909.] 



Ak']'. I. — On a Neiv Species of Leperditia from the 

 Silurian of Fas-s, Neiv South Wales, 



By FREDERICK CHAPMAN, A.L.S., F.R.M.S, 



National Museum, Melbourne. 



(With Plates I., II.) 



[Read 15th April, 1909.] 



Preliminary Remarks. 



The princij^al published descriptions of the Yass Silurian 

 fauna are to be found in C. Jenkins' paper " On the Geology of 

 the Yass Plains/'i and Prof. T. W. E. David's '•' Report on the 

 Fossiliferous Beds, Yass. "2 The former author records '' Pter- 

 inea " and " ModiolojJsis " from the horizon whence our speci- 

 mens were obtained, and it is probable that our Leperditia and 

 Jenkins' Modiolopsis are one and the same. In the vertical sec- 

 tion in Prof. David's Report, ostracoda are recorded from bed 

 L, associated with Pterinea laminosa ( = (?) Rhoinhopteria) and 

 '' Sjjirifer yassensis'' ( = S. aff . plicatellus, L. sp.). Beyond 

 the above references, no other information concerning the Yass 

 Lejjerditiat appears to have been recorded. 



In November, 1903, Mr. A. J. Shearsby, F.R.M.S., of Yass, pre- 

 sented to the National Museum, among other fossils, a good series of 

 Leperditiae on blocks of shaly micaceous mudstone from Clifton- 

 wood, Yass, N. S. Wales. This genus of ostracoda has been 

 recorded from Australia,^ but no species have yet been described. 



1 Proc. Linn. Soc. N. S. Wales, vol. iii., 1878, pp. 21-32. 



2 Ann. Rep. Dept. Mines, N. S. Wales (for 1882), 18^3, p. 148 ; and especially sections 

 (vertical and horizontal), with accompanying notes. 



3 Prof Ralph Tate, in his "Cambrian Fossils of S. Australia," Trans. Roy. Soc. 

 S. Australia, vol. xv., 1892, p. 187, records two forms of Lejjerditia in the Cambrian Lime- 

 stone of (?) Curramulka, one of which he says " has much resemblance to L. dermatoides, 

 Walcott." These examples of Tate's have been kindly lent me by my friend Mr. W. Howchin, 

 and in addition two other specimens from Mr. Sweet's collection will presently be described. 



