54 



Notes on the Extinct Volcanoes of Mount 

 Gambier and Mount Schank, South Aus- 

 tralia. 



By Walter Howchin, F.G.S. 



[Read June 4, 1901.] 



It is somewhat remarkable that the interesting volcanic dis- 

 trict, situated in the south-east of this State, has not been 

 more thoroughly examined and described. No monograph, 

 such as would do justice to the subject, has been, attempted, 

 and the strictly scientific literature, dealing with the extinct 

 volcanic phenomena of the district, is very limited. The Rev. 

 Julian E. Woods, in his work, "Geological Obsei^A^ations in 

 South Australia'" (1862), devotes three chapters to the subject. 

 Mr. Wood's descriptions are vivid and painstaking, and have 

 long been regarded as the main work on the subject. In 1884 

 Mr. H. Y. L. Brown, the Government Geologist of South Aus- 

 tralia, published a brief report "On the Lakes in the Mount 

 Gambier District,"' accompanied by geological sketch plans 

 showing sections through the principal volcanic mounds, lakes, 

 and deposits. If to these references we add a paragraph in 

 Professor Ralph Tate's presidential address before the Philoso- 

 phical Socfe'ty of Adelaide in 1879, we have noted the prin- 

 cipal sources of information that have been published on the 

 subject. There can be little doubt if the country was ex- 

 haustively examined much new light would be thrown on the 

 origin, character, duration, and other aspects of the volcanic 

 activity. 



The present notes are of slight pretensions. They do not 

 aim at exhaustive treatment, but are the fruits of a few obser- 

 vations made during a recent brief visit to Mount Gambier and 

 neighborhood. 



Mount Gambier. 



Mr. Woods advocates the view that the lineal chain of 

 lakes at Mount Gambier represent a series of crater vents. 

 He also believed that in the case of the Blue Lake and the 

 Valley Lake subsidence preceded, and probably gave ri&e to 

 volcanic, vents in these positions, and that, in all, there were five 

 craters in the Mount Gambier group.* Sections of the mate- 

 rial forming the volcanic mound can be seen in many places, 



* Op. cit., p. 250, et seq. 



