32 ANNIVERSARY ADDRESS. 



The Tertiary formations are perhaps better known than those 

 to which I have already referred. More attention has been given 

 to them on account of the rich gold-bearing, stream tin and 

 diamondiferous deposits which they contain. Nevertheless, not 

 only has very much to be done in the way of elucidating the 

 modes of occurrence of the deposits themselves and the nature of 

 their embedded fossils ; but the interest attaching to the work is 

 increased by the discovery, which such work leads to, that the 

 rich deposits are far from being exhausted. Mr. T. W. Edgworth 

 David's geological survey of the Vegetable Creek Tin-field has 

 shown that there are 49 miles of stanniferous deep leads of which 

 only about three miles have been worked out since the 

 commencement of tin mining in 1872. During this period tin 

 ore to the value of £1,975,560 has been raised from the deep leads 

 and shallow drifts in this district. Similar geological observations 

 in reference to the gold as well as the tin bearing deposits have 

 been made by myself and the officers of our Survey in other 

 mining districts, proving that the deep leads will afford 

 employment for miners for many years. These ancient 

 fluviatile deposits have been extensively covered with basaltic 

 rocks, indicating volcanic activity at different times during the 

 Tertiary period. Two of the most remarkable of the points of 

 eruption in New South Wales are Mount Conoblas near Orange, 

 and Ben Lomond in New England. The microscopic examination 

 of our various igneous rocks especially those associated with the 

 occurrence of gold, is at present engaging the attention of 

 the Geological Surveyors. Professor Liversidge has already 

 communicated to this Society the results of some good work in 

 this direction. The subject needs the co-operation of many more 

 observers ; and it is one which other microscopists of this Society 

 might readily take up. 



Eew of the geological periods possess greater scientific interest 

 than the Post Tertiary or Pleistocene. In it the characteristic 

 fauna of Australia enjoyed a flourishing state of existence, as 

 evidenced by the vast number of marsupials, some of gigantic 



