The Causes and Phenomena of Earthquakes. 73 



distant locality. It will probably be found that its focus was 

 under the ocean, not many miles to the eastward of the mouth of 

 the Hunter. 



Looking at the condition of Australia, so far as is known, and 

 to the history of such shocks as have been before recorded, we 

 are, I hope, at present, as physically considered, in no fear of any 

 such great convulsion as has often overthrown cities and deso- 

 lated vast regions in a few moments ; and yet when we read the 

 records of such disasters as have been chronicled, we have no 

 right to presume that this country may never be so affected. 



Although in New South Wales, Queensland, and Western 

 Australia, so far as we know, there is not any authenticated fact 

 of even an extinct volcano (for the often puffed performances of 

 Mount Wingen are nothing but the effects of burning coal 

 seams), yet in Victoria and a part of South Australia there are 

 numerous extinct craters which up to the present epoch have 

 erupted, whilst the north and north-east coasts are belted by 

 islands, which, as in New Guinea, the New Hebrides, and New 

 Zealand, contain active craters or boiling springs ; but these are 

 at least 1000 miles distant. 



In more ancient geological epochs, earthquakes and eruptions 

 must have been wonderfully active even here. The flow of basaltic 

 lava, basalt, trachyte, and greenstone and other igneous rocks, 

 now exhibited as intrusive or bedded or overflowing masses, must 

 have worked great changes in the strata then affected, and though 

 no distinct foci of eruption can now be distinctly perceived, yet 

 such there must have been, only obscured now by subsequent 

 processes of geological change. 



In this way noticing the numerous points of such outbreaks, 

 we come to see how in pre-historic and ancient geological times, 

 Australia, as an Archipelago, was distinguished by eruptions 

 subaerial in part, as well as submarine, though not of the identical 

 character of some of those which are numerous in the Pacific 

 Islands and the Malayan Archipelago. 



Considering the briefness of the period (onlv eighty years) 

 since New South Wales was first occupied by civilised men, and 

 the real ignorance or indifference of many of its first occupants, 

 as well as the gradual way in which exploration has extended, it 

 is not strange that we have but few early recorded examples of 

 earthquake shocks. 



The few, however, that ' have been rescued from oblivion, are 

 sufficient to justify the belief that numerous others have passed 

 unrecorded ; though my own conviction is, that I have myself 

 felt several, of which no other memorial remains than my own 

 solitary memoranda. 



It may be well, first of all, to enumerate such as are undoubted 

 occurrences of the kind, and arrange them in a tabular form. I 



