168 GEOLOGY AND PETEOGRAPHT OP CLAEENCETOWX-PATEESON DISTRICT, i., 



Therefore it is hoped that the present scheme will prove useful in that it 

 is suitahle for the whole of the type area and lends itself to application, hy com- 

 parison and correlation, to other areas. 



It is pertinent here to mention the relation of the proposed scheme of sub- 

 division to that used by Professor Benson in his work on the Currabubula Dis- 

 trict. The three stages described here cannot in any way be correlated with the 

 three "portions" of the Kuttung Series described by him. In fact, it is fairly 

 clear, that the representatives of the Kuttung Series at Currabubula belong 

 chiefly to the upper Glacial Stage of that series, and that the Volcanic and 

 Basal Stages are poorly, if at all, represented in the succession of volcanic rocks 

 and sediments in that district. 



We now proceed to a detailed description of the stratigraphy of the Series. 



(i.) Basal Stage. 



The tliiekness of this division varies from 1800 feet at Wallarobba to about 

 2300 feet in the vicinity of Clarencetown. The stratigTaphy of the Basal Stage 

 does not require much description. 



The. tuffs show current bedding in many places, of the type indicating de- 

 position by water. The whole of the strata in this Stage give evidence of rapid 

 accumulation for the most part, and exhibit many features characteristic of con- 

 tinental deposits. The matrix of the conglomerates, when fresh, is very hard 

 and of a uniform medium grainsize, and much of it contains fresh grains of 

 orthoclase felspar, so that it presents some of the characteristics of an arkose. 



About fifty feet from the top of the Basal Stage there is a horizon con- 

 taining plant remains. As the matrix is in most cases a pebbly tuft', the plants 

 are not very well preserved as a whole, but good examples of Stigmaria and of 

 Lepidodendron veltheimianum have been collected on this horizon from Clarence- 

 town and Mai-tin's Creek. Former records only indicate the finding of indeter- 

 minate species of Lepidodendron in the Kuttung Series, but there is in places 

 quite an abundance of L. velthe-imianum, the identification of the specimens be- 

 ing kindly confirmed by Dr. Walkom. There "is no possibility of the host of 

 these remains being large fragments of rock derived from pre-Kuttung units. 



This horizon has proved of distinct stratigTaphieal value, as it has been 

 found at a number of localities between Martin's Creek and Clarenceto^,n, where 

 large areas of conglomerate and tuff occur, the stratigraphy of which, but for 

 the occurrence of this plant-bearing horizon, would have been vei"y obscure. 



(ii.) Volcanic Stage. 



A considerable amount of detailed work has been done upon this Stage. A 

 number of sections have been carefully measured and of these five have been 

 drawn to scale and are given as Text-figures. 



In the following discussion of the stratigraphy concise descriptions of the 

 essential features of the various rock types will alone be given, as the detailed 

 and final consideration of the identity and petrography thereof wiU form the 

 subject of subsequent work. 



The basal group in the Volcanic Stage consists of andesites and andesitie 

 pitchstones, in general called the Martin's Creek type. At Wallarobba, in a 

 railway cutting about half a mile to the north-east of the railway station, both 

 the hornblende-andesite-giass and the lithoidal andesite are found in association. 

 The sequence is, lithoidal andesite 6ft., andesitie pitchstone 2^ft.. and lithoidal 

 andesite 12ft. The junctions between all the types are quite sharp. The lithoi- 



