188 



SOME GEOGRAPHICAL NOTES ON A MODEL OF THE 

 NATIONAL PARK AT MT. FIELD, TASMANIA. 



By Professor Griffith Taylor, D.Sc, B.E., B.A., F.G.S.^ 

 F.R.G.S. 



Plates XXIX., XXX., and Five Text Figures. 



(Read 5th December, 1921.) 



Early in February, 1919, I had the pleasure of visiting 

 the Tasmanian National Park with a party organised by the 

 Hon. Secretary to the Park Board. The whole journey was 

 filled with interest to the geographer, especially as my sus- 

 picions of a glacial topography were abundantly verified by 

 the fine examples of cirques, moraines, erratics, and glacial 

 lakes which I identified on the plateau. 



I collected topographic data sufficient to construct a 

 rough contour map (Plate XXIX.), using the reconnaissance 

 survey of Mr. Propsting and others as a basis. From this on 

 my return I constructed the model which is illustrated in 

 Plate XXX. Owing to the pressure of other research, I was 

 unable to complete a memoir on the glacial features, and 

 these have since been worked out with great care and success 

 by Mr. A. N. Lewis, M.C. ^D 



There are a few aspects of the problem which do not 

 appear in his lengthy memoir, and I feel that the geogra- 

 phical literature of Tasmania is so scanty that these brief 

 notes may not be out of place. 



The most striking feature of the region perhaps is the 

 marked parallelism of the valleys. The Plateau is so dis- 

 sected that in plan it is somewhat like a gridiron (see Fig. 

 1), with three or four main ridges all trending north-west 

 to south-east. Almost the whole area consists of one geo- 

 logical formation, a medium-grained dolerite or diabase, so 

 that we are not concerned here with dip or strike topography. 

 Jointing is a more probable cause, and a reference to Tas- 

 mania as a whole shows that the major tectonic features 

 have the same direction. I have elsewhere (p. 176, "Aus- 

 tralian Environment," 1918) drawn attention to this "grain"; 

 which is well seen in the three main lines of weakness in the 

 island. These are the Tamar-Macquarie lineament, the Lake 

 St. Clair-Derwent lineament and the Macquarie Harbour- 

 Gordon lineament. (See Fig 1.) 



(1) P. & P. Roy. Soc. Tas., 1921, pp. 16-36. 



