546 



I. — Introduction. 



The southern Flinders Ranges form a belt of highlands 

 extending from Crystal Brook to Quorn, from which latter 

 town they pass into the more extended hill-country of the 

 northern Flinders Ranges. The southern Flinders, on their 

 western side, exhibit a fault-scarp bordering the sunken area 

 of the great rift-valley of South Australia; and on their 

 eastern side are bordered by the Willochra plains, which also 

 form a sunken area. Mount Remarkable, near Melrose, 

 forms the most distinct and precipitous scarp on the eastern 

 side of the ranges. The mount is eight and a half miles in 

 length, has a height of 3,178 feet above sea-level, and rises 

 2,022 feet above the plain at its eastern foot. The view of 

 the mount, as seen from the plains (pi. liv.. fig. 1), with its 

 sudden rise and steep slopes, is very striking, and obtained 

 for it from Eyre/ 1 ) the explorer, in 1840, the appropriate 

 name by which it has since been known. 



The following geological notes are based on observations 

 made during several visits to the locality. An area so exten- 

 sive and so greatly disturbed would require many months 

 of careful investigation for the mapping of its more detailed 

 features, the time for which I have been unable to spare, 

 but the larger geological features now presented are of such 

 an interesting kind as to justify, I hope, the publication of 

 the same. 



Previous literature bearing on the subject is limited to 

 Selwyn's Reports, published as a Parliamentary paper (2) in 

 1859. Selwyn ascended Mount Remarkable, observed "a 

 small greenstone (hornblende and felspar) dyke on the east 

 flank," and published a generalized geological section of the 

 mount. In this section he shows a major unconformity as 

 existing between the slates (which are represented as the 

 fundamental series) and the quartzite — the latter having a 

 much lower angle of dip and is represented as forming the 

 cap of the range. Selwyn's hasty examination of the ground 

 may account for his failing to recognize the true structure 

 of the mount, while the great width of the quartzite outcrop 

 might well deceive even a skilled observer in a cursory 

 examination and be taken as evidence of an unconformable 

 series. The slates, instead of being, as shown by Selwyn, 

 older than the quartzite, are really newer and occupy a posi- 

 tion stratigraphically superior to the latter ; and, in the present 



(i) Journal of Expeditions in Central and Southern Australia, 

 vol. i., p. 44. 



(2) Geological Notes of a Journey in South Australia from 

 Oape Jervis to Mount Serle. 



