Notes on ilie Geologtj of the Country around Goulburn. 63 



POSITION OF STRATIFIED ROCKS. 



The position of these stratified rocks claims a moment's atten- 

 tion. These strata have experienced alterations in position as 

 striking as those displayed in mineral aspect and chemical com- 

 position ; originally loose mud and sand, they are now slaty or 

 quartzose rocks ; originally in a horizontal position, on some 

 ocean's floor, they now stand on edge, or are thrown into troughs 

 and arches on the dry land. We cannot wonder at their meta- 

 morphic condition if we admit a degree of chemical action upon 

 them at all commensurate with that of the physical forces, to 

 which they owe their present position. 



The dip of the rocks is shewn by the arrows upon the map. 

 They are never horizontal for any distance ; they are contorted 

 in many parts, as along the Shoalhaven ; their prevalent dip is 

 to the westward at angles varying from 10" to 45', and often 

 higher, but a few reversals to the eastward do occur ; in the 

 neighbourhood of Point Ondyong at Lake George they stand on 

 end. The general strike of the strata is N. by E., and even in 

 parts of the Shoalhaven where the contortion is greatest, this 

 uniformity of strike is preserved. It corresponds with the 

 direction of the mountain ranges. To the unequal waste of the 

 various inclined strata is due the very existence of many hills 

 and ranges. A good instance of this can be observed in the 

 Governor's Hill, near Goulburn, which consists of soft sandstone 

 at its base on the eastern side, but of hard quartzite on the 

 top. The limestone partakes of the dip of the strata with which 

 it is interbedded. 



No unconformability has been detected in any part of this 

 stratified series. The rocks rarely exhibit fractures, even on the 

 smallest scale ; and no faults have been observed. 



Excepting the limestone, no stratum is characteristic enough 

 to be recognised wherever it may occur ; it therefore becomes 

 important to inquire whether this can aid- us in determining the 

 thickness of the rocks. Looking at the various outcrops of 

 limestone, and connecting them by lines, it is remarkable that 

 they make their appearance along the general strike of the 

 strata : three well defined lines of this sort can be made out, one 

 stretching from the Wambeyan Caves through the outcrop in 

 Strathard, at Limestone Point on the Cookbundoon, Long Reach 

 on the Wollondilly, to Jerrara Creek ; another from Baiter's 

 Creek on the Shoalhaven, through many points of outcrop to 

 "Windellama Creek ; and the third starting a few miles north of 

 Goulburn, thence across 'the Wollondilly at Baw Baw, thence to 

 the west of Lake Bat hurst and to Boro. 



But, as the prevalent dip of these beds of limestone is west, it 

 is more likely that they are distinct beds than the separate 

 portions of one deposit. 



