ANNIVERSARY ADDRESS. 29 



noticable from its graptolites, and the Upper Silurian, probably 

 Wenlock and Ludlow, also in Victoria, the latter undoubtedly 

 extending into New South Wales. 



To add to the perplexity some of the strata contain fossils 

 characteristic of the formation below them mingled with others 

 belonging to the overlying series : these have been named by the 

 Rev. W. B. Clarke " passage beds " for the sake of convenience 

 for classification. Nor have the natural thickness and order of 

 sequence of the strata composing each series been ascertained ; 

 their associated minerals and fossils have been but little 

 determined ; their position and extent require mapping out ; and 

 the suitability of their soils for agricultural and pastoral purposes 

 is not yet fully known. I may here, in passing, say that an 

 accurate survey of the Coal Measures in the Maitland district has 

 just been completed by Mr. T. W. E. David, B.A., F.G.S., 

 Geological Surveyor. This locality was selected by me for a 

 detailed Geological Survey because the Middle and Lower Coal 

 Measures are therein well represented ; for it is only by careful 

 survey of such typical localities that information of value can be 

 acquired for the elucidation of the same Coal Measures elsewhere. 

 It is gratifying to know that Mr. David's work has been very 

 useful, not only in scientific results as regards the order of 

 sequence of the different strata and of their associated fossil 

 remains ; but also from a direct practical point of view, in the 

 discovery of two coal seams which have since been opened for 

 mining operations. I mention this as an instance of the 

 importance of scientific work, such as it is the object of our 

 Society to promote, which may especially " tend to develop the 

 resourses of Australia, and to illustrate its Natural History and 

 Productions." 



Then again the geology of the Clarence River series and of the 

 Narrabeen Shale beds requires investigation, and the succeeding 

 Hawkesbury Sandstone formation upon which Sydney stands and 

 ^vhose yellow rock cliffs give such picturesqueness to our coast 

 and harbour scenery and to the valleys in our Blue Mountains 



