233 



floating ice as the conditions under which tliese beds were laid 

 down is undoubtedly correct. There is no instance of a hard 

 glacial pavement that would indicate land-ice as the a^'ent, 

 but a continuity of deposit which shows that the material 

 was laid down in an area of uninterrupted sedimentation. 



Extent. — The beds occur in their natural order with the 

 related divisions of the Cambrian series throughout the 

 Mount Lofty and Flinders Ranges. In the anticlinal and 

 synclinal foldings of these ranges the beds under description 

 make scores of outcrops, over an area which may be regarded 

 as a great triangle, having the Onkaparinga at its southern 

 apex, and the Willouran Ranges, near Hergott, on the one 

 side, and the extreme north-east of the Flinders Ranges, on 

 the other, forming the base-line. Measured north and south 

 they have an outcrop of 450 miles, and an east apd west 

 direction of 200 miles. The beds have been subjected to much 

 faulting, which, in the case of strike faults, have repeated or 

 obscured the beds, aiid by dip faults have broken the con- 

 tinuity of the outcrops. 



A more detailed description of these beds is reserved for 

 future publication. 



A paper was read before this Society in April of last 

 year by Messrs. Iliffe and Basedow, in which the authors gave 

 a totally different explanation of the beds in question. This 

 paper was not printed in the Society's Transactions, but 

 lengthy abstracts from the paper appeared in the Adelaide 

 daily press- of April 5, 1905, and was supplemented by subse- 

 quent correspondence. Tne theory expounded by the essay- 

 ists was that the beds in question owed their existence, '"not 

 to glacial but to cataclysmic action," in the form of a 

 ''thrust conglomerate," and that this ''extends along a line 

 of fault from the south of Adelaide far into the north." The 

 '■'foreign stones" are accounted for by the supposition that 'a 

 fundamental series was first folded between overlying beds,, 

 the fold closed forming thin alternations of different litho- 

 logical composition, and the older were then thrust up among 

 the younger." Great emphasis was laid upon the "deforma- 

 tion produced by stress due to earth movements occurring in 

 the rocks adjacent to and bordering on the conglomerate m 

 the Sturt Valley." I do not intend to discuss tb'^ points at 

 issue between Messrs. Iliffe and Basedow and myself. I do 

 not think it necessary to do so. The observations of the 

 gentlemen referred to were limited to one locality, and their 

 theories are entirely unsupported by the facts. The fulness 

 and clearness of the evidences for the o-lacial oris"in of these 

 beds have received the unQualified acceptance of se\eral dis- 



