152 HORN EXPEDITION — SUMMARY. 



cuiiifcrciiti;il in their uccuncuces? The insularity of its gcograiiliic ixj.sitiou was 

 partially maintained during the deposition of the Desert Sandstone (Uj)per 

 Cretaceous*) — a fresh water area, ur largely so, r<'j)lacing the maritime i ne. 

 Favourable conditions then ensued in Pliocene times which permitted migration 

 over the largely reclaimed lacustrine areas. It was then that ISadisies pcriiijlata 

 and B. Jodiualis spread south and south-west; so also the Angaselhe liut under 

 new modilications ; whilst there may have been received a few northern types, out 

 of which have been evolved Badistcs iiraiiditubcnulata^ J>. icattii, Clilofitis squaniii- 

 /osa, 77icrsi/cs sublevata and T. adcockiana. The linal climatic phase was the 

 creation of the Dry Zone, which eU'ectually cuts off migration in a southerly 

 direction." 



It may perhaps be pointed out that tln^sc; suggestions with I'egard to the times 

 at which the IMolluscan fauna was established in the Centre are not altogether 

 satisfactory. 'Jlius Professor Tate in the paragraph pievious to the one (juoted 

 says " the Endodonta' and Flannnulina belong to genera largely Tasmanian." 

 llis suggestion that the species of Microphyura, Cliaroj)a (Endodonta) and 

 Flannnulina were acquired when the Larapintine Region formed an insular mass 

 is somewhat dillicult to understand, as if the Centre were, in this insular state then 

 it could have but little chance of giving or receiving MoUusca to or from any other 

 part and especially in the south easterly direction, such as any Tasmanian atlinity 

 would imply. 



it seems scarcely necessary to go back so far to find a time at which the 

 special forms mentioned by Professor late passed across into or out of the Centre. 

 There can be no doubt, as Professor Tate and others have repeatt'dly pointed out, 

 that in oi' aljout Pliocene time the climatic conditions of the Centre were favourable 

 to animal life. If as Professor Tate suggests it was then that Badistes pcrinjlata 

 and B. Jodinalis spread south and south-west and that " there uuiy have been 

 received a few northern types, out of which have been evolved Badistes grandi 

 tuberciilata, etc.," why will not the same favourable time sullice for the migration 

 of such forms as Microphyura hej/iiciai/sa, which is sj^ecifically identical with the 

 Queensland and Northern Territory form ? 



What it wt)uld ajjpcar, judging not only fiom the Rlolluscan but from the 

 Maisupial and Lacertilian fauna, to be necessary to postulate, is that the centre 

 has been connected, in such a way that emigration of animal life was faii'ly easy 

 across the intcrsening country, with (1) the north and north-east, and (2) with the 



* This is rufuiTcd to as Supra Crctacuous in tliu Ocolo^'.v Reiwrt ami the KulliiiH Downs as Upper Cretaceous. 



