Soils and Soil- formers.] SUB ANT ARCTIC ISLANDS OF NEW ZEALAND. 753 



calculated on the ash-free peat from Jessbeck, in Schleswig-Holstein, the layer at the 

 surface contained 0-08 per cent. ; at 7 ft., 2-1 per cent. ; and at 14 ft., 4-05 per cent, 

 nitrogen. The original peat contained 2-72 per cent., 7-42 per cent., and 9-16 per 

 cent, of mineral matter respectively at the different depths. A more detailed exami- 

 nation of the non-nitrogenous matter of peat was made by von Feilitzen (18), and 

 his results confirm those of Detmer as regards the gradual increase in the proportion 

 of carbon concurrentl}' with the increase in depth. Notwithstanding that the peat 

 rapidly loses two prominent non-nitrogenous constituents — cellulose and furfuroids — 

 the peats investigated by von Feilitzen were of the hochmoor variety, derived from 

 vegetation which thrives when the surrounding water is deficient in lime and other 

 plant-food. Absence of lime has been shown by Hilgard to be favourable to the 

 accumulation of carbon. 



Miller (5), in discussing Detmer's results, states that we possess no evidence 

 that the vegetation from which the lower layers of peat were derived was identical 

 in composition with that of later growth, but the high percentage of nitrogen at a 

 depth of 14 ft. must be mainly due to losses of oxygen in combination with carbon, 

 as well as losses of hydrogen, probably as marsh-gas. 



Hall (13) remarks that the nitrogenous portions of vegetable matter resist decay 

 longer than the carbohydrates, and hence tend to accumulate, so that an old sample 

 of deep-seated peat is richer in nitrogen than a more recent sample taken from nearer 

 the surface.* 



The total nitrogen in these island soils is exceptionally high, even for a humus 

 soil, at the respective depths given. Analyses of European peats quoted by 

 Nystrom (6) give the lowest nitrogen content as from 0-95 per cent, to 1-7 per cent., 

 and one instance is given of a sample as high as 2-7 per cent. 



Eliminating the inorganic portion of those series of soils which were taken in 

 successive layers at Camp Cove, Snares, and Campbell Island, it will be seen that 

 the top layer is the richest in nitrogen, but some of the lower layers are richer than 

 those nearer the top. The record is, of course, fragmentary. No face of humus 

 was sampled lower than 8 ft., and if it were possible to sample a section to 14 ft. 

 much more conclusive evidence might be obtained. 



A remarkable difference between the soils of Auckland Island (which is also 

 true of the Campbell Islands, so far as they have been examined) and those of 

 Ireland is that in the case of the last-named country the high bogs, according 

 to Ryan (9), contain little ash, but the low or fiat bogs contain more ash ; whereas 

 in the Auckland Islands it is the upland soils which contain the most ash. 

 This is probably due to bog-slides taking place more frequently on the uplands 

 of these islands, and carrying down much mineral debris, which finally becomes 

 incorporated with the soil. If there is a check in the declivity, or a dense 

 forest, it is easy to see how the humus soil in the vicinity may be considerably 

 enriched by the clay and debris being spread over it. On the other hand, if the 

 gradient is unchecked, and the slide has sufficient impetus to carry it through the 

 forest, it may sweep all before it to the sea, in'which case it is possible that on the 

 old scar we may get a Pleurophyllum meadow 'established at sea-level, as at Fair- 

 child's Garden. Evidence of both kinds of bog-slides was seen at Auckland and 



* The italics are mine. It will be observed that he does not say. " at the surface.' 

 49— S. 



