39 



Sketch of the Geology of the Southern 

 and Western Parts of the Lake Eyre 

 Basin. 



By Gavin Scoulab, Corresponding Member. 



[Read September 7th, 1886.] 



Plate III. 



The following notes were made in the course of a journey 

 which I undertook in September last as far north as Anna 

 Creek and Mount Margaret. 



Geology of the Country Around Farina. — The secondary beds 

 thin off to the south, dying out about ten miles south of the 

 Railway Station. The higher lands in the neighbourhood are 

 chiefly occupied with hard calcareous beds, apparently non- 

 fossiliferous, whereas the flats, which have been denuded by 

 Leigh's Creek, consist of a powdery gypsiferous material. 



Geology of the Country passed through between Farina and 

 Anna Creek Head Station. — Eor the first thirteen miles we 

 passed over a plain of very uninteresting country to the 

 geologist; there then appeared in the distance, to the westward, 

 white gypsiferous cliffs, which to some degree relieved the 

 monotonous aspect of the landscape. We shortly after entered 

 upon the low swampy lands of Hay's Creek. After crossing it 

 we halted on a small sandhill on the eastern side, about two 

 miles above its junction with Leigh's Creek. Mount Nor'- 

 West now began to loom ahead in the distance to the north- 

 west. 



By making a detour I had the opportunity of examining the 

 debris of a deserted well, which had been dug in the thin 

 covering of secondary strata which rests upon the primitive 

 rocks a little below the crossing place, but did not find any 

 fossils nor discover anything interesting about the material 

 which had been taken from it. After crossing the creek we 

 travelled upon a ledge of old primitive rocks which runs across 

 the bed of the creek from 15 to 20 yards. No doubt these 

 beds constitute a portion of the old slate series, which appear 

 from beneath the cover of secondary beds far more frequently 

 in the north country than is generally supposed. The strike 

 of these beds is approximately north and south, and the dip is 

 westerly. 



"We then ascended a slight rise, from 15 to 20 feet, on to a 

 stony plain of secondary age that stretches away for several 



