90 



sand, to drop its burden, only allowing the finest suspended 

 particles to be carried further, which gave rise to extended 

 loens deposits bordering the sand deposits to the south-west. 



It will be remembered that sandstone ridges were described as 

 occurring in this portion of our journey, covered with accumula- 

 tions of a fine-grained loam. The only possibility of explaining its 

 occurrence in this country is by assuming its origin as subierial. 



As it was ascertained that the sea-winds are active as far 

 inland as this, and that also a barrier of high ridges is to be 

 found there, these facts in themselves make the accumulation of 

 loess easily explicable. 



How deep these subanial deposits are could not be ascertained. 

 According to their levelling tendency it was found more copiously 

 deposited in the valleys of the bed-rock, where it was sometimes 

 found excavated apparently by running waters to a depth of 

 four to five feet, showing on the perpendicular faces thus produced 

 the genuine land-loess structure. 



The occurrence of such distinct courses of superficial water 

 also points strongly to an uncommonly plentiful rainfall, pro- 

 duced, as explainecl above, by meeting of land and sea-wind. 



Minor features of the surface formation of this section are ; — 



Olaypans. — They were of moderate extent, and few in number. 

 It will be remembered that when leaving the Devonian forma- 

 tion of the Sutherland Ridges, and entering the formation which 

 has been taken as Mesozoic, claypans were mentioned as occur- 

 ring thereabout. They also \\-ere met before and after crossing 

 the metamorphic rocks described as occurring between Camp -53 

 and Camp 55, and again when leaving the Mesozoic formation, 

 and entering the Palieozoic formation after having passed the 

 Queen Victoria Spring. There they were partly covered with 

 efflorescent salts, leading to so-called salt-lakes. 



Should not the constant occurrence of claypans on or near the 

 boundary of the sedimentary and the metamorphic formation 

 point to an ascent of subterranean waters, which finds its way to 

 the surface along the joints of the bed-rocks. 



Even if it should not terminate in an actual egress of a spring, 

 a perpetual wetness of stratified rocks must lead to a minute 

 disintegration of its particles of physical action, as, for instance, 

 freezing of its interstitial waters, as well as chemical action by 

 depositing the saline matter by volatilizing, and forming thus a 

 deposit of clay, gypsum, and salt, a combination of minerals of 

 which all the claypans and salt-lakes consist. 



The occurrence of an extinct mound-spring within the 

 neighbourhood of claypans also points to an efflux of sub- 

 terranean waters, which was one time even strong enough to 

 penetrate to the surface in a continuous flow. 



