THE VICTORIAN NATURALIST. 165 



the thickness of tuff exposed less. From about 30 feet of tuffs at 

 the inside end of the cliff, they lessen till they disappear rather 

 more than half-way along the bay. From there on the low bank 

 is basalt, which forms the rocky point known as Cleghorn's 

 Point. From this point on along the coast no more tuff was 

 seen. 



Along this section the same general features are observed, 

 but the dips are more pronounced than at Stuart's Cliff. They 

 range up to 25°, and, though very variable, seem usually to be 

 northerly or north-easterly into the bay. The included blocks 

 are similar ; the largest is of basalt, of about 5 feet diameter as 

 exposed. Granite of similar types occurs, but in smaller blocks. 

 Again, a number of large blocks — not all — belong to one bed. 

 Under the lava stream the usual dull brownish colour of the tuff 

 is altered to bright red. 



About half-way along the bay the tuffs are traversed vertically 

 by a wall of compact basalt in which a large block of tuff is 

 included. This basalt is continuous, so far as can be ascertained, 

 with the lava stream above. At one place it is somewhat vesicular 

 and slaggy. There are no indications which would point to in- 

 filling of a cleft from above. It may therefore be regarded as a 

 dyke, though it cannot be traced to continue across the beach. 

 It forms a slight projection in the line of the cliff. The neigh- 

 bouring beds are somewhat bent in different directions. 



The lava stream is traceable, with a uniform slope, to near the 

 foot of the steep slope of Mt. Callender. This hill is a scoria 

 cone. The surface in the upper parts is thickly strewn with 

 scoriaceous basalt. It rises to about 360 feet above the lake, 

 about 200 feet of which is on a steep slope. No natural sections 

 occur, and the only excavation worth notice is a small hole made 

 on the east side, which shows irregularly aggregated scoriae. A 

 slight hollow exists on the north-west side, due, probably, to 

 weathering. At its base on the south is a more marked depres- 

 sion of small size, due, perhaps, to slips. On the south-east of the 

 mount, above where the lava is first noticed, abundant water 

 issues, indicating a more impervious material below — that is, the 

 lava. Above this small slips appear to have occurred, the scoriae 

 slipping on the rock surface below. Northward neither the road 

 nor railway has any cutting. Lava outcrops near a lagoon north 

 of the mount, and from there eastward a concretionary ironstone 

 is the chief material exposed in the shallow drains. It may 

 possibly be due to decomposition of volcanic ash. 



A low ridge connects Mt. Callender with the lower hill before 

 mentioned. Callender Bay thus receives no stream of water, but 

 only the water from the surrounding slopes. It is said to be 

 shallow, with a muddy bottom. 



An attempt to estimate the position of the vent or vents may 



