320 



The rock gives no evide-nce of having been faulted or subjected 

 to tectonic movements that might have caused crush breccia- 

 tion. It seems probable that the brecciation was caused by- 

 some form of enterolithic movements induced by chemical and 

 crystallizing processes during the alteration of the rock by a 

 partial metamorphism. 



4. The rock-structure seen in the Burra limestone is quite 

 distinct from the others of the Brighton series described in 

 this paper. This arises from the several reasons that the 

 beds at the Burra are at a slightly lower horizon than the 

 others described, they were laid down under different 

 conditions, and have been subjected to greater alteration than 

 in the case of the other localities dealt with. The wavy and 

 concentric structure sometimes seen in the Burra limestone 

 (pi. xviii.) is an interesting illustration of how susceptible 

 limestones are to deformation under tectonic processes. 



Bel TANA (Flinders Range). 

 PI. xxi. 



Beltana is a small township situated on the great 

 northern railway line, between Quorn and Marree (Hergott), 

 353 miles from Adelaide. On the eastern side of the township 

 a small creek has cut into its bank, exposing a section of thin 

 limestones and calcareous shales of Upper Cambrian age. The 

 beds are in nearly horizontal position and give no evidence 

 of tangential slides or crush in the rock as a whole. At some 

 points, however, the beds are strangely broken in such a 

 manner as to suggest some form of intraformational breccia- 

 tion. The thin layers of limestone, when in position, are 

 about an inch in thickness, but they pass into a confused 

 conglomeration of shale and limestone fragments, many of the 

 latter being rounded as though having been subjected to 

 attrition. In the same vertical cliff there are to be seen 

 larger fragments, about a foot in length, that have a 

 laminated structure and have been acutely bent so as to have 

 the appearance of a closed fold. An isolated fragment of this 

 kind, enclosed in the horizontal shale bed, proved at the 

 time of observation a most puzzling feature. 



The upper part of the section consists of a thin-bedded 

 limestone, the surface of which shows a number of angular or 

 subangular fragments of various sizes and shapes that have 

 become united into a solid slab (see pi. xxi). When viewed 

 on the vertical face it is seen that the brecciation goes down 

 into the limestone to a depth of several inches. 



It would seem, from appearances, that the contorted 

 fragment seen in the shales of the middle portion of the 



