258 C. A. SUSSMILCH. 



Raymond Terrace are included for comparison. A com- 

 parison of the norms of these two rocks with that of the 

 Gloucester Buckets is as follows: — 



Gloucester Buckets, 





Gloucester. 



Quartz 



42-60 



Orthoclase ... 



45-59 



Albite 



7-34 



Anorthite ... 



0-28 



Corundum . . . 



— 



Diopside ... 



0-86 



Hypersthene 



— 



Magnetite ... 



1-39 



Ilmenite 



0-30 



Hematite ... 



0-16 



Mount Bright, 1 



Paddy's Hill, 



Pokolbin. 



Raymond Terrace. 



44-0 



31-1 



42-8 



3-3 



7-3 



53-2 



1-1 



1-7 



1-8 



1-7 



0-9 



— 



0-1 



0-9 



0-2 



0-6 







0-2 



Magdeburgose 



Westphalose 



Magmatic name Magdeburgose 



Both these rocks occur on about the same horizon in the 

 Kuttung Series as the Gloucester rhyolite. It will be seen 

 that the rock for Mount Bright is practically identical with 

 that for the Gloucester Buckets although these two locali- 

 ties are about 70 miles apart. The rock from Paddy's 

 Hill on the other hand differs from the first two in being 

 very rich iu potash and correspondingly poor in soda. 



B. The Intrusive Rocks. 



Some dolerite dykes have been noticed intruding both 

 the Devonian and Carboniferous strata, but these were too 

 decomposed for petrological description. One very inter- 

 esting (?) intrusive rock was found however, which merits 

 description. This was found associated with the Gloucester 

 rhyolites in the Gap, a valley cut through the Gloucester 

 Buckets Range about a quarter of a mile south of the 

 Gloucester Bucket Trig. Station, It cannot yet be definitely 



1 The Geology of the Eruptive Rocks of Pokolbin N.S.W., by W. R. 

 Browne and A. B. Walkoin. This Journal, Vol. xlv, 1911, p. 379-407. 



