346 AUSTRALIAN, SOUTH AFRICAN, AND INDIAN COAL-MEASURES, 



But let us consider the series which follows. The Wairoa- 

 Otapiri series, with a fauna of very mixed character, com- 

 bining some surviving Permian forms with a great majority of 

 distinctly Triassic character, and a few which are Jurassic in 

 Europe, has been on the whole regarded as Triassic, the Wairoa 

 beds even as lower Trias. Yet the presence of Belemnites otajnri- 

 ensis, which is near B. elongatus of the English Lias, along with 

 Pleurotomaria ornata and Tancredia truncata, which are '''Oolite 

 forms," (Hector I.e. p. 71), must not be neglected. In this forma- 

 tion there are also fresh water beds, with Glossoptens, ZamiteSy 

 and Rhacophyllum. Now, looked at from the northern stand- 

 point, all our Mesozoic and post-Mesozoic formations appear of a 

 mixed character, like what are called Passage beds in an area 

 of definite formations. And in the same manner the corres- 

 ponding formations in the northern hemisphere would present 

 to the Antarctic geologist, who had commenced with our 

 Australasian and South African fossils and had studied these 

 alone, a similar confusion and mixture of heterochronous 

 characters. Yet in view of the much more rapid and extensive 

 dispersal of animals, and especially of marine animals, than of 

 plants, and the great preponderance of the Holarctic region in 

 abundance and variety of forms, both vegetable and animal, in 

 view also of the evidence of a general drift of these forms to the 

 southward, at least since the commencement of Mesozoic times, 

 and taking into account the generally feeble character of the 

 return current or reraigration towards the Equator, by which 

 some types are creeping north from the now sunken Antarctic 

 continent and its still extant outliers in New Zealand, Tasmania, 

 and Eastern Australia, South Africa and South America, we may 

 come to a general conclusion that a large number of contem- 

 porary northern types found fossil in any southern marine for- 

 mation indicates a nearly synchronous but later period for the 

 southern than for the northern equivalent ; so that a Southern 

 Cretaceo-jurassic Fauna should be considered as synchronous with, 

 or even a little younger than the European Cretaceous, and a 

 Liasso-triassic assemblage, on the same principle, as Liassic; except 



