336 Transactions. — Botany. 



within five miles of the opposite coast. North of Parengarenga 

 the district widens, so that from Cape Maria van Diemen to 

 the North Cape is a distance of nearly twenty-five miles. 

 Most of the district is comparatively low-lying. Doubtless 

 Bay is separated from Eangaunu Harbour by a narrow strip 

 raised only a few feet above sea-level ; and all round the 

 shores of Eangaunu Harbour and up the valley of the Awanui 

 as far as Kaitaia the country has a very small elevation above 

 the sea. At the head of Ohora Harbour, in many places 

 around Parengarenga Harbour, at the back of Spirits Bay, 

 and at Tom Bowline's Bay are extensive stretches varying 

 from 10ft. to 25ft. above high-water mark. The only hills of 

 any height are those immediately to the north of Mangonui 

 Harbour, which attain a greatest elevation of 1,045ft. Mount 

 Camel, situated on a narrow tongue of land between Ohora 

 Harbour and the sea, reaches 804ft., and in several places 

 along the extreme northern coast the hills vary from 800ft. to 

 1,000ft. in height. 



A slight sketch of the geology will be sufficient, more 

 especially as full particulars can easily be obtained from Mr. 

 McKay's report. The oldest rocks in the district consist of 

 Secondary or Palaeozoic strata of somewhat uncertain age, often 

 associated with heavy bands of igneous rocks, mainly syenites 

 and diorites. This formation is well developed near Mangonui, 

 at the southern extremity of Ahipara Bay, at Mount Camel, 

 and at many places along the coast from Cape Maria van 

 Diemen to the North Cape. Cretaceo-tertiary strata, con- 

 sisting mainly of hydraulic limestones, firestones, shales, and 

 sandstones, occupy the belt between the Oruru Eiver and 

 Awanui, and also occur in several localities around Parenga- 

 renga Harbour. Upper Miocene beds, composed of sands and 

 sandy or marly clays, are also developed to the north of 

 Parengarenga. A volcanic breccia of Pliocene age, very 

 similar to the breccia so well developed at the Manukau North 

 Head, is seen at the eastern end of Spirits Bay, from whence 

 it stretches to Tom Bowline's Bay. The whole of the re- 

 mainder of the district, comprising much the largest portion 

 of its area, is occupied with Eecent deposits. These consist of 

 swampy or alluvial deposits, chiefly developed around Eanga- 

 unu Harbour and between it and Ahipara, and also occupy- 

 ing a considerable area around Parengarenga Harbour ; of 

 ancient sand-dunes, now consolidated and covered with vege- 

 tation, and which form the backbone, as it were, of the 

 narrow tract connecting Ahipara with the North Cape penin- 

 sula proper; and of sand-dunes of much more recent date, 

 still bare of vegetation, and drifting inland with every gale. 

 These recent sand-dunes are heaped up against the older 

 ones, and occupy a considerable portion of the coast-line, 



