BY A. B. WALKOM. 115 



the following series in the other States are of the same age as 

 the Walloon Series: the Artesian Series, Clarence Series, and 

 Talbragar Beds in New South Wales; the Jurassic strata of the 

 South Gippsland, Cape Otway, and Wannon areas of Victoria; 

 the Leigh's Creek beds in South Australia; part of the Lower 

 Mesozoic strata of Tasmania; and the marine Jurassic series in 

 Western Australia. 



An account has been given of the probable geological history 

 of Eastern Australia between the close of the Palaeozoic era and 

 the beginning of the Cretaceous period, and it is evident that the 

 Lower Mesozoic rocks are, with a single exception, of freshwater 

 origin. Their exact mode of origin is not definitely settled; it 

 has been shown that the basins in which they were deposited 

 must have had some outlet; deposition may tlien have been in 

 inland lake-basins with a river-outlet, or the deposits may repre- 

 sent accumulations under fluviatile conditions. 



The geological history of the area is illustrated by a series of 

 palseogeographic maps of Australia and the South-western Pacific 

 region, representing the probable distribution of land and water 

 at different stages in Lower Mesozoic time. 



EXPLANATION OF PLATES I.-IL 

 Plate i. 

 Map of Queensland showing the distribution of Lower Mesozoic rocks. 



Plate ii. 

 Geological Sketch-Map of South-eastern Queensland showing the areas 

 occupied by the Lower Mesozoic rocks. 



