The Queensland Naturalist. 
July, 1925 
28 
the complete lioe of ancestry of any forms considered 
must he available, that a knoAvled^e of the extent to 
■which converfrent evolution has been influential must be 
accessible; lhat a deep effort to attack the problems of 
distribution by payiiip' ^ireater attention to that com- 
bination of structure, function and environment which 
we term Eeolooy, and Avhich has characterised a bi<; pro^ 
]>ortion of the mor(‘ truly scientific botanical research of 
later times. Geolo^^ical evidence in support of land 
connections is often hailed, but we must bear in mind 
that in most cases the evidence is not j^'eolojiical. ])ut 
palaeontolopdcal, that is to sa^^ it is based on a know- 
ledge of the distribution of extinct animals and plants, 
the invest ifiation of which must he exclusively morpho- 
loji’ieal. The palaeontoloji'ivSt is really a biologist, and 
his mode of interpretinj:’ the distribution of forms is 
akin to thar adopted by many biologists. 
When we come to consider the problem of land 
bridges strctchiujr across oceanic areas, ^eolo^ieal evi- 
dence should be essentially of a dynamic nature, and such 
CA’idenec would appear to be nou-available until a more 
exact knowledge of earth physics is accessible. When 
this help is obtainable, many of onr problejns of distri- 
bution mi"ht he simplified and there could be reflected 
therein a distinct advance in oui’ knowledge of the 
actual relationship of many animal and ))lant forms. 
There is indeed in the present state of our knoAvledjje 
much truth in the statement that inter-continental land 
bridges cannot be proA'cd by knoAvn facts of the distri- 
bution of animals and plants, but if a land bridge could 
be proved by some other moans then from the facts of 
distribution Ave could in a eomiiarativc Avay state Iho time 
AA’hen that bridge broke dOAvn. 
In aiiA' survey of the history <d the Australian fauna 
and flora Ave have at hand consideiabk* biological a!id 
geological information of a re1ial>lc nature, such as the 
existence of a large sea in (’rotact'ous times s(‘])arating 
Avestern and eastern portions of Ihe uoav continuous 
Australian Continent, and the decided intrusion of a 
^Malaysian element into our Xorthern flora, and to a eon- 
sidt'rahle ext('nt into cemtain groups of our fauna, such 
iis the iusocts. Tiieso factors Avould ap])ear to be beyond 
dispule. but in addition eeidain land bridges liaA'e been 
SAiggested to (‘xplain the consanguinity of life forms 
in Australia and other parts of the Southern Hemisphere. 
