34 INAUGURAL ADDRESS. 



We have nothing at all approximating to the imbrication of one 

 system by another, as in the geological succession of the British 

 strata, where each has a determinable base and cover. Here, it 

 may be said, that for the most part we have neither base nor 

 cover ; the overlying system being, most frequently, vastly re- 

 moved in time from that which underlies. Thus the Lower 

 Cretaceous rocks of Australia rest directly on Archaean, Cambrian, 

 or rarely Carboniferous ; nowhere are they in actual sequence with 

 the next older system, that of the Ipswich Coal-series. The 

 Cambrian has no Palaeozoic cover in Australia ; the Upper 

 Cretaceous beds are hundreds of miles away from the nearest 

 marine Eocene. 1 consider, therefore, that the definition of the 

 stratigraphical boundaries of our rock systems is one of the 

 most important tasks which should occupy the attention of our 

 Geological Surveys. The difficulty that besets the stratigraphical 

 geologist is complicated by the phenomenon of groups of strata 

 separated by a physical break having the same assemblage 

 of fossils, as is the case with the Desert Sandstone and Rolling 

 Downs Systems and between certain sub-divisions of the Permo- 

 Carboniferous in Queensland and New South Wales. 



The faunal peculiarities of the several formations are, moreover, 

 such as to raise the question — are we right in adopting the chrono- 

 logy of the European School ? 



Jukes*', in speaking of the Palseozoic rocks and fossils of 

 Australia, preferred always to speak of them only as Palaeozoic, 

 and forbore to discuss the question of their identity in time with 

 the Silurian, Devonian, or Carboniferous periods of Europe, for 

 which even the identity of one or two species (if it occurs) is not 

 altogether sufficient evidence. 



Perhaps we may not be far wrong in regarding our Cambrian 

 and Ordovician as the homotaxial equivalents to those kno\ATi by 

 the same names in Europe ; and though we have a fauna Silurian 

 in its composite character, yet it does not present such a sub-division 

 into life zones as is well kn(Jwn to the European student. The 

 limits of the Silurian and Devonian, and of the Devonian and 

 Carboniferous, seem so ill-defined that it is questionable if the 

 middle term exists as viewed from a European or North American 

 standpoint. Then we have the palseontological overlap of the 

 Palaeozoic and Mesozoic in the Newcastle Coal-series, and probably 

 something analogous between Mesozoic and Cainozoic. Certainly 



•Phj's. structure of Australia, pp, 21, 22; 1850. Man. Geology, 2nd. edit., p. 408 ; 



