28 
GRAPTOLITES OF AUSTRALIA 
Diplograptidae have been correctly determined and a great 
number of those forms referred to D idy mo gr aphis (sensu 
strict o) are probably incorrectly identified. One feature, 
however, must not be overlooked, and this is that the records 
have in many cases been made from exact localities ; and this 
in the case of Sir F. McCoy’s papers, owing to his official 
connection with the Survey, is of peculiar value, as the 
precise position from which the fossils came is recorded both 
by him and on the Geological maps, and we are thus 
frequently able to check the records in a very effective way.” 
Discussing the sequence, he commented on certain species 
that seem anomalous in other countries. The form he named 
Leptograptus antiquus (39, cf. Ill), though not perhaps a 
typical member of the genus, is certainly not a Didymo- 
graptus. It has since been made synonymous with Bryo- 
graptus (111). Didymograptus Mfidiis (now D. protoMfidus 
(151)) dies out long before PJiyllograptus typus has dis- 
appeared and is survived by a Clonograptus and two or three 
species of DicJiograptus. He emphasized the fact that in the 
Northern Hemisphere Clonograptus flexilis is associated with 
forms which characterize the next higher horizon in Victoria. 
The case of C. rigidus is also striking, for though in America 
it is, according to Amii, associated with Loganograptus, yet 
with us the latter genus does not appear till Phyllograptus 
typus and closely allied species have become extinct. In 
regard to this statement of Hall’s it should be stated that 
Loganograptus has since been found at a much lower horizon 
(131). 
Hall discussed the composite fauna of the Lower Ordo- 
vician in regard to the Lancefield, Bendigo, Castlemaine and 
Darriwil Series. Apart from the Castlemaine Series he does 
not mention limiting forms. He states that the Darriwil 
Fauna “differs from the typical Castlemaine fauna by the 
almost entire absence of Didymograptus caduceus and the 
appearance of Lasiograptus and Glossograptus. Trigono- 
graptus and several species of Didymograptus and CUmaco- 
graptus occur, while T etragraptus serra and Loganograptus 
still persist. This series appears to mark the close of the 
Lower Ordovician as in the succeeding rocks Dicrano- 
graptidae put in their ax>pearance. ” Thus he regarded the 
appearance of Dicranograptus as heralding the incoming of 
the Upper Ordovician. 
He commented on Upper Ordovician species, pointing out 
that no stratigraphical work had yet been done. 
In regard to the Silurian, he identified Clonograptus 
