19 



enquiry, the shell named, but not described by Prof. 

 McCoy as Unio Dacomhii,* from the Wannon Secondary beds 

 of Victoria, the first detailed notice we appear to have of 

 Unio in Tertiary or Post Tertiary formations, is the descrip- 

 tion by Capt. F. W. Huttonf of two New Zealand species, 

 U. AucMandica, G-ray, from the coal formation of Dunstan, 

 Otago, and 17. inflata, Hutton, from the Ototara group of 

 Morley Creek, Southland. In a very instructive and able 

 paper on " The comj^osition and extent of certain Tertiary 

 beds in and around Launceston," Mr. R. M. Johnston;]: has 

 given many facts which have a direct bearing on the subject 

 under discussion. He has shown that previous to the later 

 volcanic jDeriod the valley of the Tamar was occupied, to a 

 great extent, by a large lalce, in which was slowly deposited 

 beds of lignite., with laminated clays and sands, denominated 

 by him the Launceston Series, and containing the remains 

 of an extensive flora. The Launceston Series is divided by 

 Mr. Johnston into three zones, from the lower of which 

 specimens of a TJnio have been obtained at Muddy Creek, on 

 the W. Tamar. The size of this lake is computed to have 

 occupied " not less than 600 miles of what now is the most 

 fertile and cultivated portion of the Island of Tasmania." || 



The next mention we have of the occurrence of the genus 

 Unio in Australasian Tertiary beds is that by my friend and 

 former colleague, Mr. C. S. Wilkinson, P.Q-.S., Grovernment 

 Geologist for N. S. Wales. In his " Report of Progress for 

 the year 1876," Mr. Wilkinson places on record that " In the 

 Home Rule Lead (G-ulgong), at a depth of 126 feet, a fossil 

 Unio was found associated with the vegetable fossils. The 

 discovery is interesting, inasmuch as this is the first fossil 

 shell of the kind yet found in the Pliocene Tertiary gold 

 drifts." § The plants referred to by Mr. Wilkinson are 

 Spondylostrohiis, Flesio capparis, and others characteristic of 

 the Victorian and N. S. Wales gold leads, described by Sir 

 Ferdinand von Mueller. The Unio, although a unique 

 specimen, was forwarded to me by Mr. Wilkinson for 

 description. After comparing it with the fine collection of 

 recent Unionidce m the British Museum, I came to the con- 

 clusion that, taking into consideration the state of preservation 

 of the fossil, it agreed sufiiciently well with the New Zealand 

 U. AucMandictis, Gray, to be regarded only as a variety of 

 that species. A description, under the name of U. AucJc- 



* In Smyth's Progi-ess Rep. Geol. Survey Vict., 1874, pp. 24 and 35. 



i Cat. Tert. Moll, and Echinodermata of N. Zealand, 1873, p. 25. 



X Papers and Proc, R. Soc. Tas. for 1873, pp. 39-47. 



|i Loo. cit. for 1874, p. 58. 



§ Annual Rep. Department of Mines, N. S. Wales, for 1876, p. 172. 



