36 GLACIAL REMAINS IN THK NATIONAL PARK 



east of Mt. Field West. It stretched down the valley 

 about a mile to a point just beyond Lake Hayes. It deposit- 

 ed a considerable pile of morainal material that now 

 stretches in a bank a quarter of a mile north of Lake 

 Hayes, and through which the Bunyip Creek has cut to a 

 depth of 50 feet. The glacier must have been melting in 

 this vicinity throughout its existence, withdrawing very 

 slowly and evenly. It deposited this considerable bed of 

 glacial till behind which L.ake Hayes now lies, and, grad- 

 ually shrinking, covered the floor of the valley above the 

 lake with debris. 



The moraine is of interest from one point. Unfortu- 

 nately, throughout the National Park the uniform diabase 

 gives little variety in the textures of these moraines, but 

 here, right in the centre of the cirque at the head of 

 Lake Hayes Valley, is still to be found a tiny pocket of 

 sandstone. This is only about 200 feet in depth, and below 

 it, as above and all round the rock, is diabase. But there 

 are several large blocks of this sandstone visible in the 

 moraine beyond Lake Hayes, over a mile from where its 

 parent bed is now to be seen. Some of these can be seen 

 behind a large clump of King William Pines on the north- 

 west side of the lake. This valley is not as extensive as 

 most of the other areas, but shews the wonderful sculptur- 

 ing action of an ice-river. 



In conclusion, our National Park can afford a student 

 of nature a comprehensive series of examples of the 

 eroding and constructing work of glaciers, enabling him 

 to study at his own back-door these mighty forces, and 

 provides an insight into the geological history of our island, 

 all obtainable with the expenditure of an insignificant ex- 

 penditure of energy and time. It is doubtful if any other 

 40,000 acres of the surface of the globe can supply the 

 variety of interests that the public of Tasmania is striving 

 to save from destruction in its National Park. 



LIST OF WORKS REFERRED TO IN TEXT. 



Reid, A. Mcintosh, 1918, "The North Pieman, Huskisson, 

 and Stirling Valley Mining Fields," Geol. Surv. Tas. 

 Bull. No. 2R. 



Waterhouse, L. L., 1916, "The South Heemskirk Tin- 

 field/' Geol. Surv. Tas. Bull., No. 21. 



