Soils and Soil-formers.] SUBANTARCTIC ISLANDS OF NEW ZEALAND. 761 



Examination of Relation between Surface Soil and Subsoils and Rocks. 



J 816-8, 821, 822. — In order to study the soil-conditions at different depths 

 below the surface, on the 26th November, 1907 (the last day of the camp at Camp 

 Cove), a trench 12 ft. long was cut, under my supervision, by the Maori boat's crew, 

 on Skua Gull Flat, by which name is designated a shallow basin-shaped cavity on the 

 shoulder of the hill 150 ft. above the boat-depot at Camp Cove. The situation was 

 chosen owing to its proximity to camp, its fairly level character, the absence of 

 timber and roots, and, lastly, its elevation. An account of the top soils and their 

 flora is given under the heading " Lowland Humus Soils." Figs. 3 and 4, p. xvi, 

 show well the scene of operations. 



The top soil (J 816), the first 18 in., was of a brownish colour, and composed 

 for the greater part of decomposed vegetable matter. The subsoil (J 817), the next 

 14 in., had a brownish-yellow colour, and contained many thick undecomposed 

 roots, while towards the junction with the clay, at the lowest part of this 14 in. 

 layer, was a thick mat of roots. 



J 818 was the 12 in. layer below J 817, and consisted of clay and partially 

 decomposed fragments of basalt. 



J 821 and J 822 were the clay layers, of 2 ft. each, resting below J 818. Thus 

 the trench was sampled to a depth of 7 ft. 10 in. Roots of Danthonia bromoides, 

 the characteristic grass tussock (allied to the New Zealand snowgrass) of the islands, 

 were traced down below the surface in the clay to a depth of 4 ft. 9 in. 



Portions of the weathered basalt having a white or pinkish earthy appearance 

 (J 833a), and unweathered basalt (J 833b), were taken from the trench at 3 ft. 7 in. 

 for analysis. 



J 819-20. — About a chain lower than the above trench another hole was sunk 

 to a depth of 3 ft. Here the clay and rocks were found at that level, and the massing 

 of the roots occurred just as in the previous trench, but only 1 ft. 8 in. below the 

 surface, being thickest at 2 ft. below the surface. A plastic clay was met with at a 

 depth of 3 ft. The two samples, soil and subsoil, were 18 in. in thickness. The 

 bottom layer is much richer in total mineral constituents soluble in hydrochloric 

 acid. A remarkable exception to any other island soil is the high content of sul- 

 phates of the subsoil. 



Humus Coarse Sandy Soil (more than 50 per cent, siliceous inorganic matter). 



J 798 is a coarse sandy soil from " salt meadow " flats at the head of North 

 Aim, Carnley Harbour. Collected on the 22nd November, 1907, to a depth of a 

 few inches only. The vegetation was Montia fontana, Cardamine hirsuta, Ranun- 

 culus acaulis, moss, sedge, Poa annua, Poa pratensis. In its content of inorganic 

 non-calcareous matter this soil, which represents only a limited area, differs from 

 any other met with. 



K 2644 was collected on the windward side of Enderby Island, above basaltic 

 cliffs, on the 8th January, 1909, to a depth of 1 ft. It contains much clay and 

 mineral matter, probably weathered in situ. Flora : English grasses, Tillaea 

 moschata, Ranunculus acaulis, Cerastium glomeratum, Rumex neglectus, Scir-pus. 



K 3047 was the subsoil taken 1 ft. below K 2644. 



