BY THE REV. J. MILNE CURRAN, F.G.S. 



175 



on the surface, so they cannot be clue to the effect of running 

 water. "We must only suppose that joints in the basalt are being 

 filled with clays from the surface by rain waters as they filter 

 through, and that every furrow marks the position of a joint in 

 the cooled lava stream. 



Division of the Strata. — Although surface indications would 

 lead to the belief that all the rocks about Dubbo should be 

 referred to the same age, we have ample evidence to enable us to 

 distinguish two formations — the Dubbo sandstones and the Balli- 

 more coal basin. 



The diamond drill boring put down near the town of Dubbo 

 showed the following section. A section I measured at Ballimore 

 gives the following succession : — 



Gvit 



Ironstone 



White shale and ferruginous sandstone 



Ironstone 



Impure fireclay 



Ironstone 



Fireclay 



Ironstone band ... 



Impure fireclay 



Irregular ironstone bands 



ferruginous sandstones and shales 



White fireclay ... 



Talus 



The fossils are equally distinct. 



Fossils prom Dubbo, 



Thinnfeldia odontopteroides. 



media. 

 Odontojjteris macrojjhylla. 

 Alethopteris australis. 

 Hymeno2^hyllites, sp. 

 Walchia, sp. 

 12 



