286 GEOLOGY ANU PETROLOGY OP' THE GREAT SERPEXTISE BELT OF X.S.W. 



seventy-five square miles aud visiting some outlying districts. Removal to New- 

 Zealand prevented the writer from continuing in further detail the mapping thus 

 rapidly outlined. Meantime, the investigations by Mr. SussmUeh and others 

 showed the widespread nature of the tluvioglacial phenomena in Carboniferous 

 rocks discovered in 1914 by Professor David, and of this work an exceedingly 

 important statement has just appeared (4). A two days* visit to C'urralndiula 

 jiaid by Browne in September, 1919, resulted in the discovery of the glacial 

 phenomena in this district also, an observation coniii-med immedi:itely afterwards 

 by Professor David. The wiiter paid further brief visits in December, 1919, and 

 .January, 1920, and noted the extension of these glacial beds, and, in more detail, 

 tlie stratigraphica' succession. While, therefore, we are now able to give a general 

 account of the geology of this tlistrict, it is obvious that much remains to l>e done 

 in the detailed study of all the formations, and in particular it must be pointed out 

 that the boundaries of the subdivisions of the sedimentary series and the estimates 

 of their thickness are only rough approximations, and no attempt has been made 

 to differentiate between the numerous igneous formations, sills, dykes, breccias, 

 etc.. grouped together as the roughly outlined Warragnndi complex. The im- 

 probability of oppi.rtunity for further detailed work in this region seems to jus- 

 tify the publication of results of our studies up to the present time. 



For the purpose of linking this study to those made in the regions about 

 the head of the Manilla River (2), the available data concerning the intervening 

 region have also been summarised. 



T'le writers thanks are due in the tirst place to his collaborators, Mr. W. R. 

 Browne and Mr. W. S. Dun, to Professor David for helpful discussion in the 

 field and in the laboratory, to Professor Lawson for his interesting palaeol)otanical 

 notes, and to Mr. F. Chapman, A.L.S., for descriptions of oolitic limestones. 

 Cliaetetes and Bryozoa. Mr. Porter, of Tamworth, first directed our attention to the 

 occurrence of fossils at Currabubula, and Mrs. Scott to the south-eastern corner o'' 

 the Parish of Babbinboon, from whicii locality she has made a large collection avail- 

 able for our study. To the hosjiitality of her parents, Mr. and Mrs. Mackay, of Allan- 

 bank, the writer is indebted for the opportunity of visiting this most interesting 

 area. The hospitality of Mr. and Mrs. Doyle, of Purle\-vvah, TVei-ris Creek, made 

 possible the examination of the upper parts of \Verrie's Creek, and to the gui<lance 

 of Mr. Hammond, of Escott Park, is due the knowledge of the Permian Rocks of 

 this district. 



(iKXKRAf- Geology of the Wester.v Zone of the Great Serpentine Belt, 

 EspECLiLLT tti'-; So.mekton-Carroll District. 



In the northern region of the Great Serpentine Belt (2) the general strm;- 

 ture is as follows: — Immediately west of the zone of serijentine, there are strongly 

 folded Devoni.an rocks, with dccasionally infolded Carboniferous rocks. West 

 from this, lie gently, sometimes stee])ly, folded Upper Devonian (Barraba) uuid- 

 st(mes with tuffs, etc., passing uj) into Lower Carboniferous maiine limestones, 

 with occasional bands of conglomeiate, limestones and tuffs, the Burindi Series, 

 on which lie a largely conglomeratic series and beds containing Carboniferous 

 plant fossils with abundant tuffs and volcanic^ rocks, to which the term Rocky 

 Creek Series was applied, the whole forming a conformable se(|uence. The two 

 Carboniferous formations are developed chiefly in a synclinal zone lying abi>ut 

 twenty miles west of the serpentine. [See (1), p. 50.3 and PL xxi., fig. 4, and 



