Hakdcastle. — On the Timarn, Loess. 407 



borne, and these — except, here and there, at low levels, scat- 

 tered pebbles and boulders of scoriaceous dolerite of local 

 origin — are among the evidences in support of the dust-heap 

 theory. 



A Buried Water-hole. — Among the numerous excavations 

 made in the loess at Timaru, the most instructive as to the 

 origin of the formation is one made to the southward of the 

 railway-station to form a site for the engine-sheds. The sec- 

 tion left by the excavation, say 20ft. deep (all numbers in this 

 paper are rough guesses), shows at the surface the remains of 

 a swampy hollow— one of scores, perhaps hundreds, scattered 

 over the Timaru Downs. Some of these hollows contain 

 pools of water after heavy rains in summer, and continuously 

 through the winter ; larger ones are never dry, and contain a 

 growth of peaty vegetation. The hollow cut through by the 

 excavation referred to was of the latter class. It once con- 

 tained a growth of peat, which had been set on fire in the 

 early days of the settlement, or possibly earlier, by aborigines, 

 and the light ashes now form a layer a few inches thick 

 beneath an ordinary black soil. The clay beneath this old 

 pool is distinctly stained blue by phosphate of iron, through 

 the action of the percolating swamp-water upon the iron con- 

 tained in the clay. This coloration extends downwards for 

 several feet, and gradually fades out. Rather more than half- 

 way down the face of the cutting the section shows the 

 remains of a similar but smaller water-hole, with a little car- 

 bonized vegetable matter lying upon the uppermost of several 

 thin layers of silt which were successively deposited in the 

 hollow, and are marked off by lines of peaty stain ; and there 

 is a repetition of the blue phosphatic stain in the clay be- 

 neath, the stain extending downwards below the base of the 

 section. In this buried water-hole we have proof positive of 

 the existence of a dry-land surface during its formation and 

 existence. Tracing it outwards, the bed merges insensibly into 

 the general homogeneous mass of the formation, but into a 

 layer of it marked by a character to be described in the next 

 paragraph. 



Subsoil Iron-ore Granules. — In every railway-cutting and 

 cliff exposed to rainfall there are to be distinctly seen several 

 bands, 1ft. or 2ft. in depth, curving in the spurs so as to be 

 roughly parallel with the present land-surface. These bands 

 project slightly from the general slope of the cuttings, and are 

 also a little darker in colour. Examination shows that the 

 darker colom* of these bands, and their relatively greater power 

 of resisting erosion by rain, are due to the presence of num- 

 bers of granules of an oxide of iron — precisely such granules 

 as are to be found in the subsoils of damp lands — numerous 

 and large in the subsoil on the margins of the surface peat- 



