BY JOHN MITCHELL. 1195 



bed' of Mr. Jenkins. Then follows an immense bed of shale or 

 mudstone which readily crumbles to mould when exposed to the 

 action of the sun and air. 



From Barber's Creek to Bowning Creek the Great Southern 

 Railway crosses the bed almost at right angles with the strike for 

 a distance of three miles, and exposes it in all the cuttings. On the 

 rises to the N. and S. of the railway, bands of flagstone varying 

 from an inch to two or three feet in thickness occur. They are in 

 general separated by layers of mudstone or micaceous slightly 

 coherent grit. Almost encompassing the mass forming Bowning 

 and Bald Hills and stretching out from it on the east to Barber's 

 or Derringullen Creek, is a bed of coarse conglomerate. In places 

 this bed has undergone much alteration, and presents a porphyritic 

 appearance, the enclosed pieces of coral having been silicified. In 

 others the change has been slight, and corals enclosed remain 

 perfect. Bowning Hill and contiguous mass is composed of 

 metamorphic rock, the base being in my opinion quartz porphyry, 

 and the superincumbent portion a porphyroid or felstone. In the 

 vicinity of Bowning township the rocks found to tne east, with the 

 exception of the limestone, recur. In the position that the lime- 

 stone should occupy, did it occur on the western side of this 

 division, is a thick bed of coarse silicious grit intercalated with 

 strata of fine, friable, micaceous sandstone, and altered shales. 

 Immediately east ot this grit is a thin bed of sinter-like rock, 

 evidently originally a coralline limestone. Also in conjunction 

 with this grit occur thin beds of quartzites and jasper. One of 

 these quartzite beds I shall designate the Atrypa Zone, because 

 of the vast number of A. reticularis contained in it. And 

 lastly advancing westward is the quartz porphyry ridge. This 

 extends W. to the Two-mile Creek, and on the Great Southern 

 Road has a thickness of about 5,000 ft. Where it has been much 

 denuded the interior shows a very granitic aspect ; and some 

 fragments of it that I submitted to the Mines Department were 

 determined to be granite. But this determination was arrived at 

 from macroscopical inspection only, and therefore cannot be accepted 

 as conclusive. South of Bowning Hill between Bowning and 



