402 PROCEEDINGS OF SECTION C. 
a more unfortunate one could hardly have been chosen. Dziprion 
nodosus, as originally described by Harkness,* was founded on 
an imperfect specimen, and shows hydrothece of a form unknown 
outside the Monograptide. Carruthers, without any remark, 
quotes it as a synonym of Graptolites becki, Barr,{ itself a 
synoym of Monograptus lobiferus, McCoy, and the reference 
appears to be universally accepted. Harkness’ specimen came 
from (Upper) Silurian beds, so that we have the peculiar result, 
that chiefly on the supposed identification of an (Upper) Silurian 
graptolite, the beds at Lisle are referred to Ordovician. If, how- 
ever, we disregard the specific identification and accept Mr. 
Thureau’s statement, that the specimen found by him was a 
Diplograptus, then the age may be anything from Lower Arenig to 
Tarannon. Mr. R. M. Johnston, in his great work on the Geology of 
Tasmania, refers the Lisle beds to the lower part of the Lower Silu- 
rian (Ordovician), placing them below the Gordon River beds, which 
do not come into contact with them, and which on other evidence 
he regards as of Caradoc age. Now it so happens that a series of 
Lower Ordovician graptolites had previously been recorded from 
Victoria, and a perhaps unconscious reference to Victorian beds 
would appear to have unduly influenced Mr. Johnston in forming 
his conclusions as to the age of the Lisle slates. The Victorian grap- 
tolites taken cognisance of by Lapworth in his series of papers on 
the geological distribution of these forms, are regarded by him as 
ranging from Lower Arenig to Llandeilo-Bala (Glenkiln), and a 
couple of Silurian species had also been recorded by Sir Frederick 
McCoy, a Monograptus and a Gladiolites (Retiolites). This was the 
state of our knowledge when Mr. Johnston wrote, so that even then 
were a Victorian comparison desired there was a wide field to choose 
from. Since then the field has been extended, for we can now range 
from Tremadoc to a yet undecided horizon in the Silurian series, 
quite possibly into the Ludlow—that is using the terms in a loose 
way, for it is by no means certain that the sequence of our forms 
will be found in exact accord with that observed in the Northern 
Hemisphere, or that exact correlation with beds there will be 
possible. 
In conclusion, it may be, it would seem, only reasonable to 
believe that a Diplograptus was found in Tasmania by Mr, 
Thureau, and, as the range of the genus was so great, that no 
definite conclusions can be drawn from its occurrence. 
No. 19—ON THE GEOLOGY OF THE COW FLAT 
DISTRICT, NEAR BATHURST, N.S. WALES. 
By A. C. Anprews, B.A. 
(Read Wednesday, January 12, 1898.) 
* Q.J.G.S. vii (1850), p. 58, pl. 1, fig. 10. + Geol. Mag. v (1868), p. 64. 
