114 LOED HOWE ISLAND. 



running in a general direction of N. 130° W. One in particular, on tlie 

 eastern side of North Bay, is very noticeable, traversing the shore-line just 

 at high-water mark for nearly the whole depth of the bay. 



At the north-east point of Ned's Beach a cellular basalt occurs, containing 

 augite and oli-\dne. The vesicular cavities are filled with a zeolite, which 

 Mr. David places in the chabazite group. At the same locality tliere is also 

 present a lateritic amygdaloidal basalt, the amygdules consisting of 

 aragonite. 



No traces of any recent lava streams, or other phenomena of the kind, 

 were noticed, nor was a crater observed. It must, however, be borne in 

 mind that the geological examination I was able to make of the volcanic 

 rocks was but a very limited one. Probably the most interesting parts of 

 the island, the extreme southern end and south-eastern portions, were not 

 reached through lack of time, and the same may be said of the north-west 

 headland. If any traces of a crater be ultimately discovered it would not 

 surprise me to iind it at or near the peculiar fractured hill previously des- 

 cribed under the name of Mount Eliza. 



Prom a microscopical examination of the rock specimens collected by 

 ourselves and Mr. Alexander Morton, Mr. T. W. Edgeworth David concludes 

 that all the Lord Howe igneous rocks belong to the Basalt Gi-roup. Those 

 of the diabasic type are probably Pre-Tertiary, and perhaps Paljeozoic ; 

 whilst the non-diabasic basalts are not older than Tertiary, and some may 

 even be Post-Tertiary. And, finally, that a vast period of time must have 

 elapsed between the eruption of the two. 



The only minerals observed were zeolites in the seoriaceous basalt at the 

 northern point of Ned's Beach and at Mutton Bird Point on the east coa&t. 



During Mr. Wilkinson's visit in 1882, the drift in several of the water- 

 courses draining from tlie mountains was prospected, and no trace of gold or 

 other metallic ore was found. 



2. Sed Clay Bed. — Immediately overlying the volcanic rocks, and between 

 them and the succeeding Coral-sand rock series, occurs a bed of stiff unctuous 

 red or yellow clay. This bed, although exposed in rather inaccessible spots, 

 does not appear to have escaped the notice of Mr. Fitzgerald, who remarks, 

 " The stratified coral passes into a very red clay as it approaches the trap."* 

 The significance of this remark did not strike me until I accidentally came 

 across this clay in situ. Its superficial area has not been traced out ; but, 

 assuming that it continuously underlies the Coral-sand rock, having been 

 detected at three separate places, its distribution must be considerable. The 

 most important exposure is at one of the small rocky bays on Wilkinson's 

 Promontory, to the east of Ned's Beach. Here the beach, between tide marks, 

 IS composed of a coarse volcanic agglomerate. The clay, which is of a 

 chocolate colour and very stiff, is visible in the cliff immediately reposing on 

 the agglomerate and four feet in thickness. In its turn it is overlaid by 

 thick masses of the Coral-sand rock, extending to the summit of the hill. 



The next section is visible in Fern Glen, behind Captain T. Nichols' 

 house, where it is a few feet in thickness, but probably less than at 

 Wilkinson's Promontory, and contains fragments of basalt rock. The third 

 exposure which came under my notice was on the low banks of the Deep 

 Creek. Now it is exceedingly probable that a diligent search along the 

 course of the gullies draining the plateau of Mount Lookout and the Deep 

 Creek Valley would bring to light a number of additional sections of this 

 interesting bed. I can only regret that time did not permit of a thorough 



* Hill's Lord Hoive Island, he. cif., p. 44. 



