GRAPTOLITES OF AUSTRALIA 
55 
Ordovician systems and incidentally explained McCoy’s 
conception which guided his investigations on Victorian 
Palaeozoic fossils when he was appointed Palaeontologist to 
the Geological Survey of Victoria in 1856 and during the 
next three decades. They also gave a number of sections and 
lists of fossils from localities indicated liy numbers on the 
plans published with the paper, and also from localities on 
the Quarter Sheets. They suggest a revised serial sub- 
division of the Upper Ordovician, viz., (1) the Gishornian 
Series (the oldest), (2) the Eastonian Series, and (3) 
the Bolindian Series. Lists of typical fossils from each of 
these series were supplied, together with a table of ranges of 
both Upper Ordovician and Silurian species. They compared 
the Victorian species with the British and showed their 
points of agreement as well as their ditferences. 
They discussed the Ordovician-Silurian boundary west of 
Melbourne and in other parts of Victoria, particularly in 
regard to the anomalies that have arisen in previous work. 
The stratigraphy of the Silurian in and near Melbourne as 
hitherto worked out is discussed at length. The basis of 
palaeontological subdivision, particularly that of J. W. 
Gregory when he divided the Silurian into two series, viz., 
the Melbournian (the lowest) and the Yeringian, is reviewed. 
They showed that the evidence conflicts with that of the 
palaeontology and stratigraphy of the Melboiirne area — ^the 
type locality of the Melbournian, which is high in the Silurian 
and the equivalent of the British Ludlow, and the area to the 
west. They proposed a revised subdivision in which they 
erected a new series, viz., the Keilorian, and substituted the 
term Yarravian for Gregory’s Melbournian. They considered 
the sequence to be — 
3. Yarravian. 
2. Yeringian. 
1. Keilorian (oldest). 
The name Yarravian is suggested in place of Melbournian 
owing to the confusion that must inevitably arise from the 
previous assumption that the Melbournian represents the 
lowest subdivision of the Silurian. The Yeringian is taken 
as the equivalent of the Wenlock on the authority of McCoy 
and Chapman. The Keilorian is characterized by the first 
appearance of the Monograptidae and comprises all those 
beds preceding the incoming of ricccivtoTicusiSf which 
marks the beginning of the overlying series On_ its 
characteristic graptolites the Yarravian (= Melbournian) 
