758 E. C. ANDREWS 



formations, however, suggests itself, and that is that the two forma- 

 tions were deposited more or less contemporaneously, the former 

 in an open but comparatively shallow continental sea, at some dis- 

 tance from a shoreline; the latter in the shallow coastal waters of 

 the same sea" (p. 80). He suggests that the marked differences 

 so well established by R. Etheridge, T. W. E. David, and W. S. Dun 

 between the faunas of the two formations would be due in such case 

 to the unlike environments. 



To Benson's field work, however, we are indebted for one definite 

 piece of knowledge which may be expected to help in clearing up the 

 tangle which has gathered round the Devonian in Eastern Australia. 

 He 1 showed that the Carboniferous in New England is actually con- 

 formable with the Devonian in that region, the sediments of each 

 age being strongly folded, the strike of the folding being north- 

 northwest approximately, as traced for 200 miles at least. 



During various geological surveys in the western, southern, 

 and northern parts of New South Wales, the writer has noted 

 that the Devonian sediments vary in appearance and structure, 

 and the results of those observations would suggest that in very 

 great measure the Devonian sea transgressed the area of folded 

 Silurian sediments as far west as the Darling, without extending, 

 however, as far in that direction as had the Silurian sea. A move- 

 ment of folding apparently occurred in the Devonian which affected 

 the eastern portions of Southern New South Wales strongly, being 

 more marked as a whole in the northern portion of that area than 

 in the southern, and more marked in the east than in the west. This 

 movement may have been revived still later, with a tendency to 

 cause Australia to grow northward and eastward as it had at the 

 close of both the Silurian and Ordovician periods, the movement of 

 sea transgression to the west and south being less during each suc- 

 ceeding period. 



This brings us to a mention of the long zone of weakness extend- 

 ing from a point somewhat south of Sydney to Queensland in a 

 direction slightly west of north. The great negative area which had 

 received the Ordovician and Silurian sediments had been changed 

 to a positive element with the close of the Devonian sedimentation 

 in the south and west. The negative area by this time had shifted 



1 W. N. Benson, Proc. Linn. Soc. N.S. Wales, 19 13, pp. 490-517. 



