17

C—2b

OmruN of Soft-umioxtiinu Deposits. The classification of soft-limestone deposits given in the introductory paragraph indicates in a general way the modes in which they originate. It will readily be understood that soft material does not afford good outcrops, and that until considerable openings have been made the origin of any given deposit may beanore'<br less doubtful. Thus, as regards the Waikari deposits, it is clear that as exposed they of limestone debris on slopes below limestone outcrops, but it is not clear whether the material has come from ■ fault-crushed bands in the rock, or has been formed by the weathering of hard limestone. It is perhaps as well to emphasize the fact that the Waikari ■ deposits are slope accumulations, of comparatively modern date, derived from limestones of Early Tertiary or Late Cretaceous age, and not bedded portions of those limestones, as has been suggested by one or two of those who have seen the deposits. Thus it becomes evident that their composition is likely to vary greatly, a fact that is indeed shown by the analyses quoted. >Un ■ !.: ■ i li r.o i-i ■'.:•;!■ 9(110 iai imii - a'-'flS- n in Quality and Quantity op Soft Limestone. The soft-limestone deposits described in this report, belong to two classes —fault-crushed material approximately in place, and detrital accumulations on or at the foot, of slopes. The material of fault-crushed bands may be expected to have much the same composition on a moisturefree basis !as : the hard limestone with which it is associated. : Detrital .accumulations, owing to the inclusion of clay and other foreign substances, on the whole must be regarded as less pure than the original limestone, but it seems to be a fact that in places, as mentioned above, some concentration of calcium carbonate has occurred. Sticli ah enrichment, however, will seldom or never apply to the whole thickness. Of the'deposit. There need be 1 little doubt, however, that considerable portions of the' various deposits are' sufficiently high in calcium carbonate to be of value for agricultural purposes. The fact that as mined or dug the soft limestone will contain */& high percentage of moisture needs to be clearly stated: In summer the greater part of this can be expelled by air-drying, but if the deposits arc to be worked in winter artificial dryingwill probably be found necessary. Although the quantity' of 'friable limestone in the Cape Campbell, Ward, and Waikari districts is no doubt large, yet a considerable amount of exploration is required before any authoritative statement can' be made. Tn estimating quantity, geological investigations of the origin arid I 'mode of occurrence will be helpful, but, above all, numerous test-pits, bores, and measurements of area "site imperative. This last statement applies more particularly to slope accumulations, which are highly variable, both in thickness and quality. Finally, the grade of material worth transporting long distances must bo determined by analysis.

' 0 I I ' ■ ' ' ■...•■' 7, NOTES OF A VISIT TO MARLBOROUGH AND NORTH CANTERBURY, WITH ESPECIAL RFKKRENCE TO (TNOONFORMITIES POST-DATING TIIK AMURI LI.M LSTONES. (By P. G. Morgan.) Introductory. The writer left Wellington for Picfon and Blenheim on the 13th December, 1915, and next day proceeded to Ward (Flaxbourne), where two days were spent in the examination of the country within reach. On the l7th December he .went to .Kaikoura, where he remained for several days. The 22rid and 23rd December were occupied in examining the neighbourhood 1 of Hundalce, the lower Conway River, and Amuri Bluff. On the 24th the writer proceeded to Waipara, and employed the'next four days in visits, lo Weka Pass, Waikari, the middle Waipara, Gorge, Cass Range, &c.

3 —C. 2b.

I Calcium Moisture, CaC0 3 on Locality. innrVT &0 -> Moisture- liemarks. (bat,u 3 ) ft , Ri((is _ per Cent. r I .( .(| ■ ' —- — •: ■■. ■ ■ —- I75T3 . ':■! :■ (1) Weka Pass Road, 72-92 Waikari (2) Waikari .. 71-31 18-47 87-46 (3) Waikari .. 60-82 19-60 75-65 (4) Waikari .. 69-50 (5) Waikari .. ! 43-30 .. .. Sample from 8 ft. to 14 ft, below surface. (6) Waikari . . 69-70 .. . . Sample from depth of 6 ft. below surface. (7) Waikari .. 59-00 '.. .. Sample from 8 ft. to 14 ft. below surface. (8) Waikari .. 93-00 Mr. H. H. Holland's .. .. , About 88 property | ...-oo ''. i .. .. . .. ! l b i ■«■ .!■■ : iii ■,- ■ i,i I SuSi U I i