Silurian. ] PALAONTOLOGY OF VICTORIA. [ Grapiolites. 
broad widely diverging forms figured in our plate. In most 
specimens the very long slender stipe observed by Mr. Salter seems 
absent, indicated by a short thicker one about 1 or 2 lines long. 
By the strong oblique light of a shaded Argand lamp, and using a 
lens of low power, it may be detected as fine as a hair and nearly an 
inch long in many specimens. I do not think this can be the edge 
of a fourth plate like Phyllograptus, as Professor Hall suggests, 
from the removal of a small thickness of rock causing it to dis- 
appear as it would if a radicle, but which would only give the same 
appearance at a different depth if it were a celluliferous plate. The 
greater number of specimens have the same number of denticles in 
given spaces as in Salter’s figure (6 or 7 in 3 lines), but as described 
there is some variation in this according with the extremes of size 
now described. I at first sight conceived the large wide divergent 
forms distinguishable as at least a marked variety from the narrow 
sub-parallel forms first noted by Salter from Lauzan Precipice, 
Point Lévis, Quebec, but the very great number of specimens I 
have now examined convince me that no concurrence of characters 
can be got to separate specifically the extremes of form here figured 
and described and that from small specimens perfectly identical 
with the original type in everything to the largest forms here 
made known there is the most gradual and irregular transition of 
characters. 
Common and exquisitely preserved in the fine whitish soft slates 
of Barker street, Castlemaine (B* 78). 
Abundant with G. extensus in the black flags of B'1, on a 
branch of the Barwon Creek, 4 miles N. of Griffiths and Green’s 
Station. 
Common in the black slates (B” 32) 4 mile N.W. of cleared hills 
on Baynton’s Range. 
Abundant in the black flags of B’ 43, Watchbox Range, north of 
granite boundary, between the parish of Glenhope and Piper’s 
Creek, sheet 51 S.W.., all the specimens here being remarkable for 
the strong development of the long filamentary radicle. Narrow, 
very slightly diverging variety in the black flags of B’ 29, 20 
Newham. 
Rare in black slates of B? 34. 
[ 31 ] 
