22 



W. S. DUN. 



by weathering, the lower ground is, in many places, strewn with 

 highly polished pebbles of banded agate, chalcedony, jasper, car 

 nelian, pink and white quartz, etc. The extremely high polish 

 which these stones exhibit may possibly be due to the action of 

 the wind and sand. 



"Occasionally highly ferruginous beds of desert sandstone are 

 met with, to the disintegration of which the red sandy s<il, which 

 covers large areas of the plains, is probably due. Intercalated 

 with the Desert Sandstones there are frequently seen beds of soft 

 white rock which has very much the appearance of kaolin; and 

 which is often mistaken for the latter; it consists, however, of 

 nearly pure silica in an extremely fine state. It has been carefully 

 examined under the microscope; but it has not been found to 

 contain any organisms. Precious opal is found in rock of this 

 character at White Cliffs in the Wilcannia District." 



Several Desert Sandstone localities have been found to 

 be fossiliferous, the only one, however, known in detail, is 

 the White Cliffs Opal-field. 



One of the problems which has exercised the minds of 

 Australian geologists for many years and has led to many 

 misstatements and misinterpretations by European writers 

 has been the question of the succession and stratigraphical 

 relation of the beds succeeding the palaeozoic formations 

 of Eastern and Western Australia. 



In 1873 Richard Daintree, then Government Geologist 

 of Southern Queensland, made the first detailed report on 

 the geology and mineral resources of Queensland. In this 

 classical work, he not only constructed a stratigraphical 

 table of the sedimentary formations, and dealt in detail 

 with the volcanic and plutonic rocks, more especially as 

 concerning their intimate relation to economic minerals, 

 but also in his sketches, showed the keen appreciation of 

 the relation of geological formations to erosion and physio- 

 graphic features. Daintree's work may be regarded as a 



