70 
GRAPTOLITES OF AUSTRALIA 
The same authors contributed (156) some notes on the 
geology of the Howqua valley. They published a map and a 
section from west to east. They identify specimens in collec- 
tions made at certain specified Upper Ordovician (Gis- 
bornian) and Lower Ordovician (Darriwilian, Bendigonian 
and Lancefieldian) localities. They discuss T. S. Hall’s iden- 
tification of Monograptus. 
W, J. Harris and D. E. Thomas (157) summarize critically 
the older classifications, and propose a modification of that 
latest in use, in which more time-significance is attached to 
the entry in abundance or “bursts” of new groups of forms 
into the faunal sequence, and the enumeration of successive 
zones in the reverse order of their deposition, which crept 
into the older scheme, is avoided. Certain of the major 
series are redefined, new serial names are introduced, and a 
Middle Ordovician division is for the first time brought 
definitely into the classification. The following is a brief 
statement of the scheme, and the correlation of the new zones 
with the older, the zone numbers for which are given in 
inverted commas. 
Lower Ordovician 
(As now restricted) 
Lancefield Series or Lancefieldian 
Lai Zone of Siaurograptus and Dictyonenia. (“L4”.) 
La2 Zone of Bryograptiis. 
La2a: Burst of Bryograptus, Tetragraptiis, primitive Didymo- 
grapti, and large Diefyonemas. (“L3”.) 
La2b: No large Dictyonemas (“L2”). 
La3 Zone of Tetragraptiis approximatus (“LI”). 
Bendigo Series or Bendigonian (as now restricted) 
Bel Zone of Tetragraptiis fruticosus, four-branched. Entry of the 
zone fossil; survival of T. approximatus (“B5”). This is one of 
the most important bursts of Victorian graptolites. 
Be2 Zone of T. fruticosus, four-branched. Absence of T. approximatus 
(“B4”). 
Be3 Zone of T. fruticosus, three-branched. Entry of T. fruticosus, 
three-branched, in force ; survival of T. fruticosus, four-branched 
(“B3”). 
Be4 Zone of T. fruticosus, three-branched. Absence of T. fruticosus, 
four-branched (“B2”). 
CJiewton Series or Chewtonian (a Series newly instituted) 
Chi Zone_ of Didymograptus protobifidus. Entry of D. protohifidus. 
Survival of T. fruticosus, three-branched (“Bl”). 
Ch2 Zone of D. protobifidus. Absence of T. fruticosus. (“C5”). 
Ch3 Zone of Didymograptus balticus. At present imperfectly known. 
Characterized by Didymograpti and Phyllograpti, and containing 
small forms of I. caducous var. lunata. (“C4”). 
