Ifi MORN EXPEDITION NARRATIVE. 



Ijaiiks, and in the water will lio foun<l a fair number of molluscs, such as species of 

 Buliiius, J>itliiiiia, and the common mussel, of which the hlacks are very fond, one 

 or two species of Estheria, and water beetles in abundance, with piobably a frof^ 

 or two. On their muddy margins fresh water crabs will sidle away towards their 

 holes in the l)anks. Plenty of little chestnut-eared linches will be flying about 

 amongst the shrubs, and perhaps a pair of graceful dotterels {^Egin/iiis nigrifiotis) 

 may be seen running about in search of aquatic insects. These arc all the animals 

 that will be found in and about such waterdioles as exist for some time during 

 the diy months. On our way back, some four months later, almost all the water- 

 holes in this district were dried up, but buiied in the dry clayey mud forming their 

 beds were clusters of operculate molluscs* and nundoers of water beetles alive. 

 The crabs had apparently all retreated into their burrows, but the Estherias were 

 all dead and their empty carapaces stiewn on the surface. 



After a day's travel beyond the Macundja we turned off slightly to the east so 

 as to pass the outlying station of Dalhousie. If possible the country was more 

 desolate than ever — long upland, gibber plains with bare flat-topped Desert 

 Sandstone hills. Across this part are scattered the well known mound springs. 

 These mounds arc often of considerable diameter, perhaps upwards of 50 feet in 

 height with a pool of often waini and sometimes even hot water on their summits. 

 The water is more or less impregnated with mineral matter Ijrought up from below, 

 and it i.s the deposition of this which has gradually formed the mound as the water 

 evaporates and the sinter or travertine is left behind. At Dalhousie the mound 

 around the spring was black with decaying vegetable matter, for the pool was 

 surrounded with a growth of rushes. Over the side of the mound the water 

 tiickles down, but the channel thus formed only extends for a short distance as the 

 evaporation is too great and the water supply too small to form anything like a 

 long stream. 



These mounds of sinter or travertine, capped with gi'cen vegetation, form a 

 striking feature in the otherwise dry and parched-up country in which they are 

 found. 



A little to the north of Dalhousie we crossed a narrow belt of country 

 characterised by the growth along the creek sides of red mulga. This is an Acacia 

 {A. cyperflphylla) reaching perhaps a height of twenty feet, the bark of which, 

 alone amongst Acacias, is deciduous and peels oil', forming little deep-red coloured 



' Rome .<!i>cdnieiis of Billiinia niistrntix \\)\\vh I tool; t'loin tlio bod of a fliiod up watcr-liole and ]nit into a tin 

 match box were alive fifteen montlis after my return to .Mellioin ne, liav in;; been shut up in the box in ni.v laboratory 

 all the time. 



