TRANSACTIONS OF SECTION C. ole 
abundant, have not been touched, and a large number of new species in almost 
all groups are known, but remain undiagnosed. 
The basis of classification is in dispute. In spite of all objections I adhere 
to the Lyellian percentage method as yielding the best results. Another method 
has been adopted by Ortmann in dealing with the Patagonian Tertiaries. It 
consists in comparing each species with species of known age in the northern 
hemisphere, deciding which is the nearest ‘ally’ or ‘representative,’ and 
referring the southern formations to those northern ones which yield the greatest 
number of ‘ relationships.’ It passes by as of no importance all the southern 
forms. Harris suggests using phylogeny pari passu with the Lyellian method. 
The objection urged against the Lyellian method is that the personal equation 
enters too largely into it, and we do not know what a species is. H. von Ihering 
has discussed Ortmann’s method fully, and objects to it. To my mind the 
personal equation is as prominent in it as in the Lyellian, and it demands an 
amount of knowledge of the Tertiary faunas of the world that no one can 
possibly have at first hand, and enormous collections, quantities of each species, 
that no museum is likely to contain. As regards phylogeny, we cannot use it 
till we know the sequence. 
Confining ourselves to the mollusca, we find Tate recognising about a dozen 
recent species in the Barwonian. Later authors have more or less definitely 
recognised about half a dozen more. As we have over 800 named species in this 
series of beds, we may double the number of recent ones without seriously 
affecting the result. 
Assuming that the Barwonian is Eocene, for some age has to be assumed, I 
have elsewhere discussed most of the genera that transgress.1 Some pass up 
from Mesozoic times, others are extensions back from younger horizons in the 
north, or from recent seas. Besides this the absence of many modern genera 
must be insisted on. It is customary for those who hold that the Barwonian 
is younger than Eocene to label all the old genera ‘survivals.’ This hardly 
settles the question. Leaving the land fauna on one side, there are some un- 
doubted survivals in the Indo-Pacific, but it may be asked, Did nothing originate 
in the southern seas and slowly migrate northwards? The real place of origin 
and age of the transgressing genera cannot be settled off-hand by northern 
standards. 
The Barwonian is divided into Balcombian and Janjukian, but their relation- 
ship has been vigorously discussed. By far the greater part of the fauna is 
common to the two. Passing by the discussions between Professor Ralph Tate 
and Mr, J. Dennant on the one side, and Dr. G. B. Pritchard and myself on the 
other, which ended, as such discussions frequently do, in a series of flat contra- 
dictions as to facts, we may consider-Mr. F. (Chapman’s position. 
Mr. Chapman asserts that the Batesford limestone is typical Janjukian, and 
appears to conclude that all the polyzoal limestones, and there are many, are 
also Janjukian. He argues on the same data that the Janjukian is the younger 
series. Tate, Dennant, Pritchard, and myself, however much we differed on 
other points, agreed that the age of the limestones must be decided by reference 
to the rich fauna of the clays. Mr. Chapman makes no reference to an inter- 
calated clay bed in the Batestord limestone from which Dr. Pritchard and myself 
collected forty-five species, mainly mollusca. Of these only one is confined to the 
type Janjukian locality, while twelve have never been found there, but are 
confined to typical Baleombian beds. The rest are common to both series. 
The limestone, then, as we asserted, is Balcombian and not Janjukian. More- 
over, we showed, by a careful examination of the area, that the limestone passed 
under clays which are typically Balcombian, and can be traced to Orphanage 
Hill, only a couple of miles away. M‘Coy grouped the Orphanage Hill beds 
with those of Mornington, that is, with the type Balcombian section. Tate, 
Dennant, Pritchard, and myself agree with the grouping, and Mr. Chapman 
still labels the Orphanage Hill fossils Balcombian in the National Museum. 
If, as Mr. Chapman asserts, the Batesford limestone is Janjukian, then the 
Balcombian is the younger and not the older member, as he asserts. The 
stratigraphical facts are unimpeachable. 
The Mount Gambier limestones must, as the contained mollusca show, be 
* Rep. Aust. Assoc. Adv. Science, Hobart, 1902; Pres. Addr. Sec. C. 
