328 Transactions. 



The special interest in this section is that it shows clearly that volcanic 

 action was going on while the sands and marls were being laid down. The 

 beds strike N. 30° W., and dip S. 60° W. at an angle of 60°, the beds 

 striking in the direction of those in "Whitewater Creek. 



In the upper part of Coleridge Creek, lying on the greywacke, are the 

 greensands ; above these again the marl, running almost along the creek ; 

 and this is succeeded by the volcanic-tuff bed, which has here no great 

 thickness. This is followed conformably by the lower limestone. These 

 beds strike north-west, and dip to the north-east at high angles. 



The pronounced effect of volcanic action on the continuity of the lime- 

 stone beds is seen clearly where this limestone crosses the creek near the 

 old sheepyards, for there it ends abruptly and the bed passes on as a 

 calcareous tuff with the same stratification. The junction has all the 

 appearance of a fault, but no sign of dislocation can be seen in the over- 

 lying well-stratified beds. 



On the western side of the basin these beds are not seen, though they 

 probably underlie the isolated blocks of limestone which occur there, the 

 surface being masked by later deposits of Tertiary age and river-gravels 

 and talus from the mountains lying immediately west. In the upper part 

 of Broken River basin, especially in Waterfall Creek, in the main stream, 

 and in Blackball or Murderer's Creek (a tributary coming in from the 

 north), exposures of the beds can be distinctly seen, those in Broken River 

 itself being most instructive. 



About a mile above the road-crossing the river runs through a narrow 

 gap of limestone dipping almost vertically, the upper portion being forced 

 over the lower, this being a subsidiary fault to a main one which runs 

 north-east, the beds on the south-east being thrown down ; the fault hades 

 with the dip, and in consequence there is a suppression of the outcrops 

 on the surface, the marls, and perhaps the overlying tuff if it really exists, 

 being cut out. The beds in contact" with the limestone are white sand 

 with occasional Avhite calcareous bands. These are succeeded by green- 

 sands, and then by a hard concretionary calcareous sandstone bed 20 ft. 

 thick, and below this lie again greensands with large calcareous concretions 

 containing fragments of saurian bones. The dip of these beds is down- 

 stream — i.e., to the south-east ; but the direction immediately changes to 

 one up-stream, and the beds are repeated in reverse order. They have 

 thus been folded up into an anticline with the eastern limb almost vertical 

 or even slightly overturned, and the limestones which originally formed 

 the roof of the anticline have been removed, but the structure is indicated 

 by remnants to the immediate south-west of the locality. The lateral 

 movement of the limestone at the gorge and the slickensided surfaces of 

 the limestone are secondary phenomena resulting from the structural move- 

 ments which have produced the folding. 



These beds dip up-stream above the anticlinal axis till just past the 

 junction with Waterfall Creek, when they take the form of a syncline, and 

 the dip of the western wing of this continues for some distance up-stream — 

 in fact, to the actual base of the series, where clay and occasional beds of 

 lignite and brown coal occur. The banks of Broken River are here very 

 high, but are thickly wooded and in places subject to slip, so that the actual 

 sequence cannot be made out. Up Waterfall Creek, however, there are 

 excellent sections of the beds between the greensands and the limestone. 

 Hutton puts in a fault as necessary to explain the structure here, but this 

 seems to be incorrect. The sequence is perfectly normal and without signs 

 of dislocation. 



