13 4 Frederick Chapman: 



the already discovered fossils were intermediate in character, 



and originated in moderately low latitudes, in the Indian Ocean 

 .geosynclinal area. The southern form probably radiating to 



Patagonia, Australia and New Zealand, exhibits variants of 

 ■ compression, whilst that found in Europe tends to inflation. 



Further data bearing on this hypothesis are furnished in regard 

 ;lo the ratio of shell measurement — umbilical width to diameter. 



For example, one of the oldest Australian specimens gave a 



ratio of 1 :2.91, as against the Bordeaux specimen, 1.2.2; whilst 

 :a younger (Janjukian) specimen from Torquay, Victoria gave 



1 : 3.26. The Kalimnan specimens are too fragmentary to 

 ■measure, but bear out this gradually decreasing width ratio. 



DJstpJbution of Aturia australts. 



Mr. Newton has already given copious notes of the distribu- 

 tion of this fossil in the paper referred to, and it will therefore 

 be unnecessary to repeat them in extenso. In New Zealand, 

 we may remark in passing, that Aturia australis, though com- 

 mon in the Lower Oamaruian, dies out before the upper beds 

 ( Awamoan) are reached. Its geological range in that area seems 

 indeed to be restricted, as was that of Aturia aturi in France, 

 Egypt, and elsewhere. Mr. Newton has suggested that the 



.'Southern Australian Tertiaries (Balcombian, Janjukian and 

 Kalimnan) represent the Lower, Middle and Upper Miocene, 

 having regard, amongst other data, to the co-extensive range 

 of Aturia therein. There are perhaps some points in favour of 

 linking up the lower beds, seeing that at Muddy Creek (Bal- 

 combian), both large and small Lcpidocyclinae are found asso- 



-ciated together, as they also are at Batesford (Janjukian), but 

 the evidence requires more support to warrant a re-adjustment 

 of the time-scale. 



Comparisons and Limitations of European Stages. 



On the evidence derived from a study of the larger Foramini- 

 fera, the Balcombian is clearly Aquitanian, so nearly as we can 

 arrive at a correlation of distant sediments. This stage was 

 included by Meyer-Eymar^ in the Upper Oligocene. Since then 

 Dollfus has favoured the inclusion of the Aquitanian in the 



9. Classification des Terrains tertiaires, 1S84-; Tongrien Middle '-Oligocene. 



[7 



f Aquitanien Upper -) 



-' Tongrien Middle '- 



Ligurien Lower ) 



