3

a—l 4.

thinner or thicker coating of loam and humus. In some parts the clay is more or less orangecoloured and in others chocolate-coloured, but frequently it is much paler and almost white. The accompanying table, very kindly supplied to me by Mr. B. Aston, F.C.S., Chief Chemist, Department of Agriculture, and to whom 1 am much indebted, shows the chemical and physical constitution of certain soil-samples collected by me. Samples 600 and 601 were taken in the rimu forest near the Opanake-Taheke Road, the former being the top layer of humus 3J in. in depth and the latter the soil beneath to a depth of 2 ft. Sample 602 is a river-valley soil of the tarairi association taken from beneath the humus layer to a depth of 2 ft., and sample 603 was from the kauri association near the base of Pukehurehu Hill, also taken to a depth of 2 ft. As for the analyses, that of 600 shows a very high percentage of available potash, so much so that it appears as if the sample had been contaminated, which is hardly likely. Otherwise it is a typical humus soil, not being much decomposed, while the nitrogen-content is high. Samples 601, 602, and 603 are deficient in phosphoric acid for ordinary crops, and the amount of potash is normal.

Chemical Analysis.

Mechanical Analysis.

C. THE NORTHERN FLORISTIC PROVINCE. As we proceed from north to south in New Zealand certain plants occur, at first in abundance, then become fewer, and finally are quite absent, others appearing and disappearing in their turn. By collating the facts re the general distribution of the species it is possible to divide the New Zealand biological region into provinces, each having certain distinguishing features, both floristic and ecological. Thus I have divided New" Zealand into a Northern, Central, and Southern Floristic Province (6), the first-named being by far the best-defined, containing as it does 120 species or distinct varieties of spermaphytes and ptcridophytes which either do not pass beyond latitude 38° S., or overstep it only for a short distance and in limited numbers. This Northern

600 ... 601 ... 602 ... 603 ... No. Classification. Humus soil ... Clay soil .... Clay soil Clay soil Loss on Air 1OT . Loss on Total Drying. Loss at 100 C. Ignition . Nitrogen. Per Cent. Per Cent. Per Cent. Per Cent. 67 1616 7817 1-770 36 10-08 22-20 0 303 32 1016 21-50 0-273 33 11-28 21-24 0268 _ Available by 1 per Cent. C itric Acid. No. Potash. Phosphoric Acid. Colour of Extract on Ignition. Reaction of Soil to Litmus. .00 101 102 103 Per Cent. 0090 0013 0027 0016 Per Cont. 0020 0005 0004 0003 Greyish-brown ... Yellowish-brown Light-chocolate Reddish-brown ... Acid. Acid. Acid. Acid.

Sample No. 601. Sample No. 602. Sample No. 603. Residue on washing Very small residue of well - worn rock - particles Small residue of worn quartz and ferrugineous particles Small residue consisting of small evensized worn quartzparticles. Nil. Nil. Nil. Stones ... Gravel ... Fine gravel Analysis of fine soil— Coarse sand Fine sand Silt ... Fine silt Clay Moisture, &c. ... Nil Nil Nil 1 percent. 23-88 „ 907 7-24 50-28 „ 8-53 „ Nil 2 per cent. Nil 7 per cent. 2909 7 56 „ 4-75 55-01 5-59 6 per cent. 16-87 5-78 4-53 „ 58-77 8-05 10000 10000 10000 Capacity for holding water... Very good Very good Very good.