George Leslie Adkin diary entry Friday 7 February 1919

Fri. Feb. 7

Attended the meeting of the geol.[ogy] section at 9am Mr.[Mister] P.G. Morgan presiding. Papers were read: "The Tectonic Conditions accompanying the Intrusion of Basic + Ultra-basic Rocks" by Prof[essor] W. N. Benson. "Loess at Timaru" by L. J. Wild In discussing this paper, Mr. E. Dobson said that the reservoir on the Cashmere Hills was sunk 35ft[foot] into loess which showed wind stratification

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+ the capillary structure from top to bottom. "The Organisation of a Geological Survey" by Mr. P.G. Morgan. The session closed at 12.10 and an excursion to the vicinity of Mt[Mount] Grey to inspect the gravels +c [etc] of the "Kowhai Series" started at 12.50 in three cars. The party consisted of 14 including two ladies. I went in Dr.[octor] Helgendorff's car with Wild, Lomas, + Miss Mestayer. Our route lay along the Papanui Road, + then north past Styx + over the Styx River, a stream similar to the Avon on a smaller scale. All the surrounding country appears dead level + very fertile, there being splendid crops of wheat, oats, linseed +c. At Chaney's the road bends towards the railway + then curves round the South Branch of the Waimak.[iriri] finally crossing it at Whites Bridge. The river flows on a fairly wide bed of shingle capped in places with small dunes. Other dunes lie on the surface of the plain just before Whites Bridge is reached. Kaiapoi Isld.[Island] is flat + fertile here + exactly resembles the plain. We passed Kaiapoi without going through the borough, + then crossed the North Branch of the Waimak. which here consists of two slow flowing streams with sandy beds + lying a few chains

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apart. The road then crossed the rly.[railway] to Bennetts, + a little beyond same the water-course known as Main Drain, an artificial cut connecting the Cust River with the Waimakariri. From beyond this point Mt. [Mount] Grey, 3055', looms straight ahead. We passed through Rangiora, crossing the other branch rly.[railway] to Bennetts immediately beyond, + then ran along to the ferro-concrete bridge over the Ashley River. The Ashley flows in branching channels on a wide bed of shingle, + is bordered on its left bank by a strip of very stony land which is evidently overflowed at times of flood. The bridge by which the railway to Culverden crosses the river is visible downstream + from this point several features of the district can be picked out: about a mile due north of the bridge are rolling downs, rising gently from the margin of the plain to a height of 1300ft. or more. On these downs are fields picturesquely divided by gorse hedges. These downs which have a mature topographic surface are, as I found later, the topographic expression of the "Kowhai Series". Away to the NNE the Cass Range, lying beyond the

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Waipara Gorge was visible; + to the NNW are the foohill [sic] peaks of the Puketeraki Range - Mts Grey, Keretu + Thomas all over 3000ft. We waited on the bridge till the other cars caught up. Photo 1/4pl.[ate] (26) Group + car on Ashley Bridge. We then proceeded, past the road to Loburn, along Carr's Road which runs round the lower slopes of the downs, then up the valley of the Makerikiri Stream, finally crossing its then dry bed. Further on the road runs imperceptibly into the basin of the Grey Stream + the downs are terraced. There are terraces along the lower course of the Makerikiri also. On the lower (south) side of the downs the small road cuttings show pale yellow clay, but their higher slopes are stony. As the road turns into the valley of the Grey high scarps showing a great thickness of brownish gravels in the upper parts, appear first on the right bank of the stream + then on its left. The formed road stops at a farm-house + from here I took photo, 1/4pl.(27) The junction ^'of E. + W. forks' of the Grey Stm.[Stream] looking downstream from the end of the formed road. We left the cars + proceeded along a cart-track which ran down to

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+ then up the bottom of the valley of the East Branch of the Grey. Also 1/4pl.(28) of valley of East Branch looking up stream. This valley has a comparatively youthful topography though the stream is now graded + meanders on its irregular valley-bottom which is very stony. For the most part the left side of the valley is a high scarp perhaps 250ft. in height with occasional steep grassy fans + "washouts" rather fantastically carved by ephemeral rain-born torrents. The upper part of the scarp consists of a great mass of brownish gravels with thin bands of clay as shown in photo, 1/4pl. (29) which is of a "washout" showing brownish gravels, with thin interbedded clays, passing downward into finer gravels, from top of cliff to base. These beds dip southward. In other places the gravels rest on marine beds - green + yellow silts + incoherent grey sand with thin seams of sandy lignite. In photo 1/4pl. (30) of gravels resting on greenish marine silts the marine beds dip south at an angle of 14° + the junction of gravels + marine beds is 10°. Collected a few specimens ^'from stream-bed' which Mr.[Mister] Speight identified for me as, cemented silicious sand, limestone +c. The East Branch of the Grey rises on the western flank of Mt. Grey + the West Branch

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in Mt Keretu. Rolling hills, limestone in their highest part, lie between these branches, + near their junction there is a conspicuous high-level terrace common to both streams. In the East Branch a flight of terraces still occurs here + there, principally on the right side of the valley, + only rarely on the left side, as there in the past the Grey cut the high scarp mentioned above. We halted opposite a huge "washout" + took a photo, 1/4pl. (31) of the party on the stream-bed. This "washout" shows the masses of gravels resting on the marine beds unconformably - an unconformity which Mr. Morgan considered "formational." I heard Dr. Cottton express the opinion that the "Kowhai Series" appeared to be of deltaic origin + it seems that this was true of the marine beds, the upper gravels being sub-aerial fan deposits built on the delta as the river built forward as a result of a huge supply of waste. Returned to the cars again fording the stream many times. Photo (32) 1/4pl. Left wall of the Grey valley showing a "dead" fan + a "washout" exposing the "Kowhai" gravels. Back to Ch-ch by outward route. Met Wright at 7.30pm + did the city the Friday night crowds affording much entertainment.