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112 south-east of the main peak is a steep rocky peak of about 1,000 ft. ; and to the south-west of the main peak are several smaller peaks, all, however, with gentle slopes. Three-quarters of a mile along the ridge to the north- east of the main peak is a small elevation known as MeGregor's Hill. 021 the south and cast the hill slopes down to the shallow waters of Otago Harbour, and at the south-western end to an enclosed bay known as Lake Logan. The gullies on the eastern and sonthem sides are of slight depth, and are occupied by small streams.

A valley of considerable breadth and depth runs down to Lake Logan, and is occupied by the Opobo Stream, which rises in a swampy arca rear the suunit of Signal Hill . On the north-west the vidge is bounded by the North-cast Valley Stream. This stream always carries a considerable volwne of water, and has croded for itsell a deep valley. The sequence of the rocks appears to indicate a great antiquity for this stream-valley. The stream bas two branches, one of which rises on Mount Cargill, while the other has worked its head back in an easterly direction, and is cutting down the saddle to the north of McGregor's Hill. The upper part of this branch is still crodling its bed, but the lower part, and also the main stream, liave reached base-level, and have filled the floor of the valley with alluvium. The North-east Valley Stream is fed by numerous small tributaries, the middle conrses of which are generally through steep-sided gullies. OCCURRENCE OF THE Rocks. The rocks of most widespread occurrence within the Signal Hill area are the phonolite of the Logan's Point type, the trachytoid phonolite of the Signal Hill type, and a basalt-for which I describe as basalt No. 1. The basalt covers the top of Signal Hill, and extends across the upper part of the depression of the North-east Valley. "The Login's Point phonolite extends from near the summit of the hill to Logau's Point, forms a steep peak on the side of Signal IIill overlooking the harbour, and reaches to a point near Burke's. The Signal Hill phonolite has rather a wide occurrence about YcGregor's Hill, and is found also in the North-east Valley, Besides these there is a distinct variety of mepitelinitoid phonolite, ocurring probably as an intrusion, on the saddle to the north of MeGregor's Hill; and there are several other basalts. The latter vary in composition from a very basic variety, orcurring as a dyke on the Main North Road, which appears to be the youngest rock described, to a variety approaching andesite, which appears to be the oldest rock exposed. The least basie of the basalts, which I have called No. 5, clearly underlies the Logan's Point phonolite at a point on the Main North Road a quarter of a mile from Normanby. In the valley below this point it is not to be found, being obscured by slips of phonolite from above. Between the phonolite and the underlying basalt in the section exposed there is a stream-deposit, will boulders derived from the basalt, proving an intermediate period of erosion. The Logan's l'oini trachytoid phonolite mass is of great thickness on the southern slope of Signal Hill, being continuous from below sca-level at Logan's Point to an elevation of 1.100 ft. near the summit. Towards the west, however, it thins outl, mil on the Main North Road there is a thickness of only 50 ft. between basalt No. 5 below and the main basalt- flow (No. 1) above. In the valley below, the Logan's Point phonolite gives place to the Signal Till phonolite, but the junction is obscure. There is dificulty also in tracing the boundary between the two rocks on the eastern side. It is