The Grajitolites of Lancfi field Beds. 175 



The following is a list of the species obtained : — 



Biyograptus victoriae, n. sp. 



Bryograptus clarki, n. sp. 



Leptograptus antiquus, n. sp. 



Didymograptus pritchardi, n. sp. 



Didmograptus taylori, n. sp. 



Tetragraptus decipiens, n, sp. 



Clonograptus flexilis, J. Hall. 



Clonograptus magnificus, Pritchard. 



Clonograptus rigidus, J. Hall. 



., ,, I'd/- tenellus, Linnars. 



Phyllograptus ? sp. 



Dictyonema macgillivrayi, T. S. Hall. 



Dictyonema pulchellum, n. sp. 

 In examining the above list we are confronted by the fact 

 that two of the genera, namely Bryograptus and Leptograptus, 

 are regarded as belonging to entirely different horizons, although 

 here occurring on the same slabs. European geologists consider 

 tlie former genus as indicative of Cambrian age, while Lepto- 

 graptus is, according to Lapworth,^ confined to the Upper Ordo- 

 vician, although one section of the family Leptograptidae, as 

 represented by Azygograptus, ranges as low as the base of the 

 Arenig. The associated genera at Lancefield forbid us regarding 

 the beds as younger than Lower Arenig, so that we must consider 

 the genus Leptograptus as of greater age in Australia than 

 in Europe. With regard to Bryograptus it is looked on by 

 European geologists, as previously mentioned, as a Cambrian 

 form, and Clonograptus tenellus is referred to the same age. 

 Didymograptus, Tetragraptus, Clonograptus flexilis, C. rigidus, 

 Phyllograptus and Dictyonema of the type herein recorded all 

 occur in the Lower Arenig of Europe and some of the genera 

 range higher. 



The stratigraphical position of the American species Clono- 

 graptus rigidus and C. flexilis adds another difficulty, since an 

 inspection of the list by Ami in the Report on the Geology of a 

 Portion of the Province of Quebec by R. W. Ells^ shows that 



1 Ann. Mag. Nat. Hist., 5 S, vol. 6, p. 27. 



2 Ann. Rep. Geol. Surv. Canada for 1887-8, iii., K, p. 116. 



