328 Albert V. James: 



Headuard Erosion. — The extremely youthful tributary streams 

 frequently become gorge-like, and tend to cut. back across the 

 fields. Farmers in this locality meet the problem by piling boul- 

 ders at the head of the tril>utary and planting hardy shrubs 

 around them in order to cheek tlie velocity of the water, and thus 

 retard the transport of material. llie early neglect to check 

 the headward erosion of youthful streams has led elsewhere tO' 

 great loss of land. A large area at G'oburg has been rendered un- 

 fit for habitation within the last thirty years, and the same will 

 occur at Aberfeldie, near the Essendon sand pits, if preventive^ 

 measures aie not taken soon. , 



Near the school at Bulla an extremely young active tributary 

 has cut back from Deep Creek and formed a canyon in decomposed' 

 granodioritc and Ijasalt. Apparently no effort has been made to 

 check the licadward erosion, and now it is completely out of hand, 

 and threatens the roads north of Bulla. The canyon is about 

 60 ft. in depth. It is not likely to deeq^en further for many years 

 as its floor is nearly adjusted to the present level of Deep Creek. 

 Lateral erosion is now rapidly increasing the area of destruc- 

 tion. 



Basalt Outliers. — A small outlier is see*!! in the south of the- 

 large granodiorite outcrop, and another in the extreme centre- 

 nortli in Ordovician sediments. They represent small basalt 

 tongues that have been cut off from the main lava sheet by river- 

 action. 



Palaeozoic Rocks. 



General Description. — The Ijedrock of the area so far as is 

 known consists of Upper Ordovician and LoAver Silurian sedi- 

 ments in the form of shales, sandstones, conglomerates, quartzites, 

 .slates and hornfels. These have been strongly folded by approxi- 

 mately east and west pressure, and the prevalence of easterly dips: 

 sugge.sts overfolding to the west. The folds pitch to 'the north, 

 and this pitch makes the strike of the strata somewhat irregular. 



Throughout the district these palaeozoic rocks have been highly 

 fractured and faulted, most of the faults being reverse strike- 

 faults. On the left baidv of Deep Creek, at the mouth of Hanging 

 Valley, is a fault ])reccia altered to hornfels by the granodiorite 

 intrusion. 



If the conglomerate (C;^), near Hanging Valley, and conglom- 

 erate Ci or C.J on Jackson's Creek, be parts of the same stratum,. 



