104 Proceedings of the Roijal Society of Victoria. 



brown and red sandstones and conglomerates, and grits 

 apparently Devonian ; while still further eastward towards 

 the colony boundary are some yellow sandstones and grits 

 bearing a striking resemblance to the lower members of the 

 N.S.W. carboniferous series. The localities where each 

 group of rock formations are found may be best described by 

 taking each group according to stratigraphical succession. 



Sedimentary Rocks. 



Loiver Silurian. 



The oldest sediments observed are the black slates of the 

 eastern tributaries of the Snowy, as at Deddick and at 

 the Yalma, where graptolites occur. These black slates 

 are vertical and finely laminar, and are evidently lower 

 Silurian. So far as known at present, these black graptolitic 

 slates do not extend further to the eastward. At Bonang 

 they are leplaced by ash-coloured and brownish shales and 

 grey quartzites, and at Bendock by fawn-coloured, pinkish, 

 and yellowish slates, shales, and tine-grained felsitic sand- 

 stones with a lesser angle of dip by from 50° to iSO°. In the 

 Broadribb Valley, the sediments are more indurated, and 

 have suffered much contortion, as seen on the range dividing 

 the Broadribb and Sardine Creeks, northerly from Mount 

 Buck, where they consist of brown, indurated sandstones, 

 and flexured hard slates full of quartz segregations. 

 On the Black Watch Creek and Goolingook the slates 

 are blue and more persistent in strike, with interlaminated 

 bands of grey close-grained quartzite. The former resemble 

 upper Silurian sediments, while the latter the lower. No 

 line of demarcation has yet been found within the area. 

 The lithological characters and angle of dip are not sufficient 

 to determine a stratigraphical horizon. The induration of 

 much of the sedimentary masses is evidently due to the 

 intrusion of granite masses either as bosses in situ or 

 ramifying dykes of hornblende (diorite) rock associated with 

 the intrusive masses. 



Uixper Silurian. 



On the range dividing the Broadribb and Snow}^ Rivers at 

 the head of Sardine Creek (northern branch) is a band of 

 greyish and whitish marlile and masses of coarse conglomerates 

 and jointed shales. I'he marble band yields some stems of 

 Actinocrinus of apparently upper Silurian facies. The con- 



