The Country round Lyell North-East 



angle towards the south-west exposed in its bed, and 

 thus must have passed the line of junction. 



We now set ourselves to work to narrow down the 

 space between these reefs and the lowest exposure of 

 the limestone, and were so far successful as to find a 

 small exposure of grit in the bank about 30 yards up- 

 stream from the uppermost reef. On the other hand, 

 a careful search revealed the presence of limestone 

 within 50 yards of this, but this was the nearest 

 approach to the junction which we were able to 

 make. 



Somewhere in this space of 50 yards lay the 

 contact of the two rocks, but as it was obscured by 

 loose material we could only determine its nature by 

 inference. 



In a small, very much weathered, exposure of the 

 limestone, which we stopped to examine on our way 

 back to camp, we found a large mass of fossil coral 

 almost entirely weathered out from the surrounding 

 mass of limestone. This was recognized as Syringopora 

 ramulosa, which is characteristic of the Lower Carboni- 

 ferous. From this determination it was clear that the 

 limestone was older than the grit, and this, together with 

 the change of dip, led us to infer that the junction 

 between the two rocks was a faulted one (Fig. 23). 



This dislocation we called provisionally the "Camp 

 Fault." 



Next morning we were up before sunrise fitting out 

 the boat which was to go down to Lyell for the canoe 

 and ropes and as much in the way of provisions as it 

 was possible to carry in addition. 



This being accomplished and the party dispatched, 



143 



