243 



The lower Finniss, or that part of the river-course mea- 

 sured from the point where the stream emerges from the 

 Mount Observation Gorge, and thence, eastward, to the rail- 

 way line, possesses some interesting features. In this section 

 of its course the river forms the dividing line between the 

 Hundreds of Kondoparinga and Nangkita, and flows between 

 banks of glacial sandstone and clays throughout its entire 

 length. Excellent sections of the beds can be seen in the 

 river cliffs at various points. 



About three miles up from the railway, in a straight 

 line, on the right bank of the stream (Section 2021, Kondo- 

 paringa), there is a vertical wall of white glacial sandstone, 

 20 ft. high, resting on a Cambrian floor and covered with recent 

 high-level river gravels. The sandstone contains pockets and 

 wedges of gravelly material, resting at all angles, in the finer 

 matrix (plate xli.). 



A short distance higher up the stream, on the left 

 bank (Section 2329, Nangkita), is another striking outcrop. 

 Here the beds consist of a very strong, compact conglomerate 

 ■of rounded stones, including varieties of quartz, quartzite, 

 schists, and numerous granites, the latter mostly decomposed. 

 The arrangement of the stones, in relation to their size, is 

 very irregular. Within the conglomerate is a large granite 

 houlder, porphyrinic in structure, and measuring 4 ft. 6 in. 

 by 3 ft. The cement of the conglomerate is siliceous and 

 sometimes ferruginous. Near the middle of the section is a 

 band of finer material, about a foot in thickness, with con- 

 cretionary ironstone nodules or "iron-boxes." Resting on the 

 top of the conglomerate is a sandstone bed much contorted 

 in the grain, a common feature of the glacial sandstones of the 

 district. The beds show a dip of 15° in the direction of the 

 valley slope (plate xlii.). 



In descending the river, from the outcrops just described, 

 the beds become more uniform in texture, fine-grained (occa- 

 sionally with coarser fragments), white to brown in colour, 

 and very variable as to cohesion. The grain of the stone, 

 brought out by weathering, exhibits some remarkable fea- 

 tures. Whilst massive to the extent of many feet in thick- 

 ness, the grain of the stone is curiously twisted, curled, and 

 contorted. These contortions are not of the nature of colour 

 lines, such as often develop by chemical change in some 

 slates and argillaceous sandstones, but original lines of deposi- 

 tion. Neither can these discordant lines of deposition be 

 referred, in all cases, to current bedding, as they are too con- 

 fused and irregular. They seem to give clear evidence of con- 

 temporaneous contortion produced by the ploughing move- 

 ment of ice-masses (plate xliii.). 



