201 



3. "Sliding Bocks' ' (pi. xxi.). These rocks occur as an 

 isolated exposure on the beach, 1| miles to the southward 

 of Rogues Point (at the outlet of Rogues Gully), and a 

 little to the north of Muloowurtie Point, in Section 49. The 

 rocks make a bold ridge, 20 feet in thickness, with a strike 

 almost due north and south and a dip east, 10° south, at 

 40°. The beach at this spot is narrow, and the Cambrian 

 beds are overlain in the cliff face by horizontal strata of soft 

 decomposing fossiliferous (Miocene) sandstones and arenaceous 

 clays. The isolated character of the outcrop, the tabular 

 form of the bedding, and the high dip of the beds as they 

 pass below sea level have given rise to the descriptive name 

 by which they are known as "sliding rocks." The beds are 

 characteristic of the lower or granular-crystalline (dolomitic) 

 portion of the Cambrian series. 



4. Montgomery's. This area is situated 14 miles to the 

 northward of Ardrossan, near jthe boundaries of the Hun- 

 dreds of Cunningham and Clinton. A ridge of the Cambrian 

 dolomites extends from Mr. Montgomery's farmstead (Section 

 172) northwards, through Section 182, into the Hundred of 

 Clinton, and is said to occur at intervals in that direction 

 for a good many miles. It was also traced in a westward 

 direction, across the public road and in rises, still further 

 to the west, in Section 173, giving a breadth of three-quarters 

 of a mile. 



In driving over the paddocks in a north-westerly direc- 

 tion the ground was spotted by numerous "swallows" 

 (saucer shaped) with "crab holes," down which the water 

 is said to rush freely in wet weather, a certain evidence of 

 underlying limestones. If these "swallows" mark the pre- 

 sence of the Cambrian limestone it must have a breadth of 

 not less than 2 miles over that country. 



The stone, for the most part, is buff coloured and 

 saccharoidal in texture, containing numerous cavities lined 

 with crystals. It is much broken by joint planes, which are 

 coated of a black colour, probably caused by a thin film of 

 manganese oxide. 



Over this extensive area no section could be seen suffi- 

 ciently exposed to show the dip of the beds. The outcrops 

 are marked either by flat, tabular patches, or otherwise by 

 loose surface fragments. In Mr. Montgomery's yard, near 

 the junction of roads (Section 172s), there is a limekiln that 

 has been excavated in the beds and exposes E.bout 4 feet of 

 rock. So far as could be judged from this limited section the 

 beds have a slight dip to the north-west. 



5. Yorke Valley. The main road from Maitland to 

 Yorketown follows this valley bordered bv ^f ^j'lgep on 



