63 



able, for the portion still remaining east of Murray- street — 

 Thorup's Eavine — still represents a thickness whicli cannot be 

 far short of 80 feet. A section of the beds in this gully, and 

 adjoining slope south of the horizontal sectional line, is as 

 follows : — 



Strata unseen, occupying the southern slope between 

 actual summit of the quarry, and where the cross 

 sectional line traverses the strata. Additional 

 depth ... ... ... ... ... 16 feet 



Gravels ... ... ... ... ... 4 " 



Gravels, sometimes conglomerates ... ... 8 " 



Micaceous sandstone ... ... ... ... 12 " 



Sandstone, fossiiiferous... ... ... ... 18 " 



Unseen immediately opposite the quarry, but lower 

 portion shown elsewhere in bed of the ravine, 

 much thinner bedded sandstone ... ... 12 " 



Total from top of quarry to bed of ravine ... 54 " 



From the escarpment at Gawler these Miocene beds extend 

 uninterruptedly inland to the east for a distance of about three 

 and three-quarter miles, and they are also exposed in many 

 isolated patches throughout western Barossa, but do not, 

 however, afford any good sections. As a rule, the beds 

 are composed of fine sand and a gravel chiefly of quartz 

 pebbles. The pebbles, though generally small, are present in 

 various forms — from the rhomb, as if newly torn from the 

 parent rock, to that of the highly waterworn and globular. 

 The f erro-arenaceous and pebbly character of the beds, and the 

 high slope of the surface of the old rocks on which they rest, 

 indicate that the portion now remaining is merely the littoral 

 deposit of the formation. Under such circumstances it is not 

 to be wondered that the organic forms are few and ill pre- 

 served. Sir Charles Lyell, in his "Elements of Geology," 

 sixth edition, page 445, where he treats of the '• Origin of 

 New Eed Sandstone and Eock-salt," says : — "It is a general 

 fact, and one not yet accounted for, that scarcely any fossil 

 remains are preserved in stratified rocks in which this oxide of 

 iron abounds ; and where we find fossils in the ISTew or Old 

 Eed Sandstone in England, it is in the grey and usually cal- 

 careous beds that they occur." 



This oxide of iron is the constituent the Gawler and Barossa 

 beds abound in ; but whether its presence has any bearing 

 upon the non-fossiliferous condition of the Gawler and Upland 

 Miocenes is a subject well worth further consideration. The 

 sparsely fossiiiferous beds at Gawler extend without a break 

 to the east, and attain an elevation of about 420 feet above sea 



