230 K. C. Andrews — The Geological History of the 



tabling species which arc closely allied, whether, for instance, 

 separated by long stretches of ocean, by wide lowlands unfitted 

 to support the species now isolated, whether isolated for a 

 long or a short period of time, or now growing under different 

 climatic conditions or on different soils; all these points should 

 be taken as the testimony of independent witnesses in the 

 matter of the classification of the plants, much in the same 

 way as the habit of the plant, its foliage, wood, corolla, calyx, 

 andrcecium, gynsecium, oil contents, and other important chem- 

 ical and morphological characters, are admitted at present. 



After all it does not alter the position materially so long 

 as the workers are consistent in their methods of classification 

 as was pointed out in 1869 by the master mind of Bentham 

 when describing the genus Cassia. 



Summary. 



It seems permissible to infer from the evidence herewith sup- 

 plied, partly as a result of the internal evidence of the recog- 

 nized modern classification of flowering plants, and partly as 

 the result of the independent testimony of the Australian, the 

 South African, the tropical, the South American, and north- 

 ern hemisphere, types of plants, that the isolation of Australia 

 from the world generally in the later Mesozoic Period was 

 preceded by a general condition of mild and moist climate 

 over the greater portion of the world with the production of 

 the various known orders of the flowering plants, and that this 

 period was associated, in its later phases, with the develop- 

 ment of families, and of genera, which showed either a tend- 

 ency to frequent open spaces, as the Composites, or an actual 

 tendency to become xerophytic or herbaceous, such as Acacia 

 or Campanula. This condition may have arisen either as a 

 development in poor soils and open exposed wastes, moving 

 parallel with the great development of luxuriant types in the 

 Cretaceous, or it may have marked a differentiation, or zoning 

 of climate, after the development, of the main orders. The 

 study of the Australian plants favors the idea that desert and 

 open waste places existed during the so-called cosmopolitan 

 mild and moist climate of the Cretaceous and the Eocene, as 

 exemplified by the perpetuation of xerophytes such as Acacia, 

 Campanula, and Ilelichrysum, prior to the isolation of 

 Australia. 



Both before and after the isolation, that is, during the earlier 

 and later great differentiations, or zonings, of climate, many 



