16 



The considerable altitude of this limestone invests it with 

 special interest. The numerous Eocene outcrops of the colony- 

 are, with this exception, all wil-;hin a height not exceeding 200 

 feet above sea level, whilst the Eocene outlier of the Upper 

 Hindmarsh cannot be much less than 1000 feet. The water 

 parting of this elevated plateau occurs about three miles north of 

 the Eocene outcrop, reaching its greatest altitude in Mount Cone 

 and Mount Jagged, the former, according to the Survey Office 

 records, is 1,380 feet above sea level, and the latter 1,230 feet. 

 The Peeralilla Hill, which is three miles further down the valley 

 than the outcrop in question, has a height of 910 feet. The exact 

 height of the Eocene beds is not known, but is probably some- 

 where between 800 feet and 1000 feet. 



I hoped, in visiting this outcrop, some evidences might be 

 found that would throw light on the stratigraphical relationship 

 of the Eocene limestone to the glacial beds of the district, but 

 neither the base nor the upper limits of the Lower Tertiary beds 

 were exposed. A great thickness of rich loamy soil forms the 

 banks of the creek at this place, and the upper posts of limestones 

 have been weathered into large boulders (after the manner of 

 limestones), with soil as cover and tilling the intermediate spaces. 

 The occurence of Eocene beds at an altitude which gives them a 

 unique position for rocks of this age in southern Australia raises 

 some interesting questions in stratigraphical geology, concerning 

 which we have at present no satisfactory solution."^ 



It is worthy of note that a few months ago I picked up several 

 sea-worn boulders of Eocene limestone of a pinky colour on the 

 beach near Sellick's Hill. In some respects they bore a close re- 

 semblance to the limestone of the Upper Hindmarsh, but differed 

 from the latter in containing rounded grains of quartz. There 

 are Eocene beds on the beach near where the pink limestone 

 boulders were found, but they appeared to possess very distinct 

 lithological features from the rolled fragments. The origin of 

 these sea-worn boulders is, therefore, a little uncertain. If de- 

 rived from the upland outcrop they must have crossed the water- 

 shed. It is perhaps more likely that they have a local origin in 

 some calcareous band which, when broken up and exposed to sea 

 water for some time have suffered some alteration in their ferru- 

 ginous constituents, and, by oxidation, have developed a pink 

 colour. Such a change, so far as I know, is not common in our 

 Eocene limestones, and may be taken into account when an 



* Professor Tate says — " Catyclismal disturbance must account for the 

 presence of fossiliferous beds of this age (Eocene) in the Encounter Bay 

 district at elevations above 600 feet. " Roy. Soc, N.S. Wales, Vol. xxii, 

 p. 242. (1888). 



