314 Transactions. — Ucolo(jii. 



have been greatly denuded, cut into by streams, and their 

 structure is exposed in many fragmentary natural sections, 

 and on a smaller scale in numerous road-cuttings. I have 

 examined them in the Geraldine, Waitohi, and Cave-Albury 

 downs, and in the Timaru plateau. The same formation 

 stretches from Albury to Fairlie Creek, and from Timaru to 

 Waimate. Everywhere near the hills the gravels present the 

 same broad features — beds of stream-laid subangular shingle, 

 and sand, separated by clays and silts. In places the forma- 

 tion is hundreds of feet in thickness ; in Geraldine Hill, I 

 believe, nearly, if not over, 1,000ft., and in the Cave-Albury 

 dovvuis it must be over 500ft. Generally the shingle is coarser 

 and the clays less numerous towards the top. Wherever I 

 have examined them the gravels are unquestionably stream- 

 laid, and generally, I believe, are of quite local origin. The 

 Geraldine downs, however, contain pebbles of a volcanic rock, 

 which must htxve come from somewhere northward, and across 

 existing drainage-lines. (These are pebbles of a dense, tough, 

 micro-crystalline rock, black in colour, with minute white 

 specks ; the stone weathers to a pale blue, of chalky softness.) 

 I htive read that there is volcanic rock at the head of the 

 Orari. There is none in the hills opposite the Geraldine 

 downs. At Timaru, the point furthest from the hills where 

 the red gravels appear, only the upper portion is exposed to 

 observation, the formation sloping just down to sea-level. 

 Here the shingle is largely replaced by finer material. About 

 two miles inland is a gravel-pit, disclosing about 30ft. of the 

 uppermost beds, two-thirds or so of which are of silts and 

 clays, the rest of small shingle, in two layers. The silts are 

 fine-bedded, and at more than one level contain vestiges of 

 having been vegetated. A boring put down at the freezing- 

 works — commencing at the bottom of a bricked well sunk 43ft. 

 into the gravels, the nature of which was not recorded — passed 

 through 40ft. of shhigle, 39ft. of clay, and 25ft. of sand, each 

 in several layers. The thickest bed was of fine yellow^ clay, 

 12ft., the base of which for about 1ft. was stained dark-brown 

 as if by humus, and contained the rust-granules common in 

 wet soils. The clays near the hills vary from a few inches to 

 10ft. or 12ft. in thickness, and they vary much in character, 

 some being fine and white, others blue, most of them yellow, 

 and of all degrees of coarseness up to silt. In some places 

 beds of clay show' abrupt changes of thickness, as if from con- 

 temporary denirdation. Some of the beds show drought-veins 

 in their upper surfaces, the mark of their having been for a 

 considerable period persistent land - surfaces under a dry 

 climate. The silts have the character of fiood-deposits, and 

 some of the clays probably had a similar origin. Others re- 

 quire further examination to decide whether they are not 



