EST CAEBONIFEEOUS AND HAWKESBUEY SEEIES, KT. S. WALES. 191 



large rolled masses in a matrix of fine silt ; and much of this silt is 

 of exactly the same peculiar bluish-green tint so characteristic of 

 these beds in this country, and which when once seen can never be 

 mistaken," &c. 



Dr. Oldham, however, does not suggest a glacial origin for this 

 formation. The next account of Carboniferous (?) Boulder-beds is 

 that given by the late Sir R. Daintree in his ' Report on the Geology 

 of the District of Ballan,' Melbourne, 1866, page 10, where he 

 describes part .of the Bacchus-Marsh beds in Victoria as : — " Strata 

 mainly composed of fine mud, dotted throughout with various-sized, 

 generally rounded, pebbles, and those pebbles mostly unknown in 

 the vicinity, and some not yet seen in place as far as the Geological 

 Survey has extended a minute examination." Some of the granite 

 boulders are stated to be over a ton in weight, and to be imbedded 

 in soft mud. 



The first suggestion of the possibility of ice having played some 

 part in the formation of these rocks was made in the same Report by 

 Sir B. Daintree ; and his views therein expressed are upheld by Dr. 

 A. B. C. Selwyn, F.R.S. &c, then Director of the Geological Survey 

 in Victoria, in " Notes on the Physical Geography, Geology, and 

 Mineralogy of Victoria," published at Melbourne in the Official 

 Catalogue of the Intercolonial Exhibition, 1866-1867, page 16. 

 The passage reads as follows : — " The character of the conglomerate 

 beds before mentioned near Darley and on the Wild Duck Creek 

 is such as almost to preclude the supposition of their being due to 

 purely aqueous transport and deposition. It is, however, very 

 suggestive of the results likely to be produced by marine glacial 

 transport ; and the mixture of coarse and fine, angular and water- 

 worn, material, much of which has clearly been derived from distant 

 sources, would also favour this supposition. Grooved or ice-scratched 

 pebbles or rock fragments have, however, not yet been observed." 



The next mention of ice-action in Carboniferous rocks in Aus- 

 tralia is made by Mr. B. L. Jack, F.G.S., Government Geologist 

 of Queensland, in his Beport on the Bowen-river Coalfield, dated 

 November 23, 1878 (printed in Brisbane, 1879), page 7. In the 

 middle (marine) series he describes conglomerate beds, chiefly 

 occurring in the lower part of the series, as follows : — " The included 

 pebbles are generally of granite, slate, schist, quartzite, and other 

 metamorphic rocks, with a few of porphyrite. The pebbles, which 

 are not always well rounded, have a remarkable tendency to arrange 

 themselves in groups in some of the conglomeratic sandstone beds — 

 a disposition which may possibly be owing to their having been 

 dropped in heaps from the floating roots of trees, but much more 

 likely from floating ground-ice. Large isolated boulders of granite 

 &c. occur here and there in the midst of strata of fine sandy or 

 muddy material. These could hardly have been brought to their 

 present positions except by glacial action." 



The marine fossils associated with these beds prove them to be 

 homotaxial with the Wollongong beds described by Dr. Oldham, 

 and of true Carboniferous age. But it is doubtful whether they can 



