BY JOHN MITCHELL. 1201 



than 300 feet. It bears a very sea-shore aspect, and marks the 

 close of the series. It has yielded a number of corals and some 

 molluscs, all probably derived from the destruction of oldei beds. 

 Among the latter are RhynchoneUa, Orthis, and a Megalodon. 



This completes a section of the eastern half of what may be 

 termed the Bowning Synclinal Basin. 



The western half differs very little from the eastern except that, 

 instead of the limestone, at the base occurs a bed of coarse silicious 

 grit, and there is some alteration of some of the lower strata 

 to sinter and quartzite, and that, after the great bed of shale, the 

 succeeding beds are fossiliferous to near the close of the series, 

 including a third zone of trilobites. 



Passing now to the western division. Resting against the 

 porphyry are some altered rocks, and beyond these a bed of shale 

 in some parts merging into impure limestone. It is rich in fossils, 

 but they have suffered much decomposition and contortion. 

 Avicula, Pentamerus, and some gasteropods are noticeable. The 

 trilobites Gromus Beaumonti, and Encrinurus punctatas are also 

 yielded. The thickness of the bed appears to be from 400 to 500 ft. 

 Adjoining this bed on the line of section, that is along the G. S. 

 Road, the rocks are hidden for some distance ; but on the Binalong 

 Road a mile further north the succeeding rocks are altered shales 

 and jasper. From the shale I have obtained minute specimens of 

 brachiopods and gasteropods. From this point to Flinter's Gap 

 (locally known as Carroll's Gap), the western boundary of the 

 parish, the rocks are all of altered character, as far as can be judged 

 from the outcrops. They consist of variously coloured cherts and 

 porphyroids of a jointy nature. Some bear indications of once 

 having been fossiliferous. Their thickness is from 2,000 to 3,000 ft. 

 I estimate the total thickness of this section at not less than 3,000 ft. 

 The distance along this section is three miles nearly, which with 

 the eastern portion gives a total sectional length of eight miles. 

 The western section is doubtless in a large measure a repetition of 

 the eastern one ; but the rocks have been subjected to greater 

 change. North and south of the sectional line the rocks appear in 

 places less altered. 



