Geological magazine . t. size. 7. Apical system of B. x 12. 8. Peristome of B. x 12. 9. B. post. amb. and iamb, of K. x 9. 10. Ant. petal of B. x 9. 11. Ant. petal of A. x 9. x4-5. IV.—Notes on Desekt-water in Western Australia. Gnamma Holes and ]Sight Wells .By Malcolm Maclaren, , IN the arid region of the goldfields of Western Australia a know-ledge of the conditions under which a search for water is mostlikely to be rewarded is of prime importance to the prospector who mayfind himself away from the beaten tracks. There is, in the summer,little hope of finding fresh water in the l
Geological magazine . t. size. 7. Apical system of B. x 12. 8. Peristome of B. x 12. 9. B. post. amb. and iamb, of K. x 9. 10. Ant. petal of B. x 9. 11. Ant. petal of A. x 9. x4-5. IV.—Notes on Desekt-water in Western Australia. Gnamma Holes and ]Sight Wells .By Malcolm Maclaren, , IN the arid region of the goldfields of Western Australia a know-ledge of the conditions under which a search for water is mostlikely to be rewarded is of prime importance to the prospector who mayfind himself away from the beaten tracks. There is, in the summer,little hope of finding fresh water in the long narrow bands of gold-bearing greenstone-schist that run from to throughWestern Australia, for both the surface and the deep-seated waters ofthis rock-formation are then salter than those of the sea. Whenunprovided with condensers for the distillation of these waters,the prospector must therefore turn towards tlie neighbouring graniticareas, and search either for * soaks or for the remarkable gnamma. Fig. 1. Cross-section of typical Gnamma hole. holes of the bare rocky ridges,sources of fresh water — theand requires little description,at the foot of granite slopes. The first and most reliable of these soaks — presents nothing abnormalThey are found in the sandy hollowsA well is sunk in the sand, and thewater is baled as it slowly percolates into the bottom of the supply may vary from a mere trickle to several hundred gallonsin twenty-foiu hours, according to the catchment, to the season,and to the permeability of the sand that has protected the water fromevaporation since it was collected in the rock-hollow. Where the absence of soaks is indicated by the non-appearanceof the slightly greener vegetation that grows over them, the travellerabandons the lower ground and searches the bare rock-outcropsfor rock-holes, or gnamma as they are called by the natives. 302 Dr. Malcolm Maclaren—Deseii-nrder in TV. Australia. Gnamma holes are most common in g
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectgeology, bookyear1864
