•?^ f 5; ' 



CRATER NEAR HERRERTON. 



By R. C. RINGROSE, M.A. 



{Redd before the Royal Society of Queensland, 24^h April, 1912) 



This remarkable spot is situated on the Upper Barron 

 River Watershed, about nine miles from Herberton, and 

 about twelve miles from Atherton, in an area of land com- 

 prising two square miles, reserved at the instance of the 

 Herberton Chamber of Commerce as a Reserve for a 

 National Park. The corrected height of the Crater tip 

 above sea level is 3,341 feet, and of the high ridge outside 

 the scrub is 3,566 feet. The bed of the Barron River 

 (Dinner Creek) encircling the Crater on two sides is 3,101 

 feet. These readings are the result oi a series of observa- 

 tions with two aneroids, and corrected by Mr. C. E. Deshonr 

 chief surveyor to the Hydraulic Engineer's Department 

 of Queensland. 



The whole of this dividing ridge between t^e Barron 

 River and Nigger Creek is either too heavily grassed or 

 clothed with dense scrub and the vegetable mould formed 

 by the decomposition of the leaves, to admit of accurate 

 observation of the rocks buried beneath. Speaking 

 generally, the whole of this divide consists of quartz 

 porphyries (composed of felspars and quartz with a small 

 quantity of mica) cut through in places by elvan dykes. 

 A large portion of the high mountain on which the Barron 

 River and Poona Creek rises is largely composed of massive 

 porphyry. The main mass of this range is often cut into 

 intrusive dykes of a fine grained porphyry known as elvans. 

 It may here be noted that the main quartz porphyries 

 and granites of the valleys of the Wild and Walsh Rivers 

 as well as many of the Per mo- carboniferous or Devonian 

 series aof these valleys are everywhere cut into by a series 

 of intrusive elvan dykes, in some places forming dykes 

 cutting through the ridges at their highest points or 

 occurring in the form of irregular compact masses. 



