364 T. W. E. DAVID. 



The recent allu vials as shown on the section, Plate 16, 

 are about a mile in width near the low level bridge over 

 the Hawkesbury River at Richmond. On the left bank of 

 the river near the bridge, the low and high level allu vials 

 quickly give place westwards to the Wianamatta Shales, 

 the uppermost member of the local Trias System. A mile 

 further west the middle member of the system, the Hawkes- 

 bury Sandstone, is seen as an inlier (see section of Plate 16). 

 From here for about four and a half miles further west the 

 Wianamatta Shales reappear attaining a thickness of about 

 250 feet between the Trigonometrical Station called 

 " Pound," and the point where the road to Grosevale leaves 

 the Kurrajong road above Little Wheeny Creek. About 

 one mile down the Grosevale road from where it leaves the 

 Kurrajong, an ostracodan sandstone was found on the 

 occasion of the visit by Mr. Card and myself. This is about 

 three feet thick and will be described in the Geological 

 Survey Memoir. At little Wheeny Creek, on the Kurrajong 

 road there is another inlier of Hawkesbury Sandstone, 

 capped further west by the Wianamatta Shales at the foot 

 of the long hill ascending to the Kurrajong Heights. 



For the first mile on the ascent a gentle easterly dip of 

 2° to 3° prevails. Then at a point about 360 yards W. 7° 

 N. from the old school building at the junction of the road 

 in portion 161 Parish of Kurrajong, the foot of the mono- 

 cline is reached at a level of about 880 feet above the sea. 

 The dip of the Wianamatta Shales at that spot is E. 12° S. at 

 20°. A little further up at the lower junction of tlie old and 

 new Kurrajong roads the Wianamatta Shales thin to a 

 thickness of only 20 feet to 50 feet, the Hawkesbury Sand- 

 stones making their appearance in all the gullies. The 

 level at the preceding road junction is about 1,066 feet 

 above the sea. At 200 yards further up the hill the dip 

 lessens to 16°, and near Mr. Powell's house at the N.W. 



