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Dudley Peninsula, about American Eiver, Point Morrison, 

 Bay of Shoals, and to the westward along the north coast. 

 From Cape AVilloughby to Antechamber Bay, it is associated 

 with gneiss and [metamorphic?] granite ; and the almost vertical 

 stratification is rendered visible at the distance of some miles 

 by the alternation of the diversified coloured massive beds. 



The prevailing dip of the strata on the north-west coast of 

 Dudley Peninsula is south-east, and the same direction is 

 observable in the micaceous beds of the gorge of the Hog Bay 

 Eiver. 



At Christmas Cove and extending westward towards Kan- 

 garoo Head along the shore-line, there are intercalated bands of 

 angular and subangular pebbles, chiefly of quartzite, and in the 

 aggregate of many feet in thickness ; the pebbles varying in 

 size from six inches in diameter to small gravel, and their 

 bedding planes are coincident with the plane of foliation. 

 These rocks are comparable with those constituting the Cape 

 Jervis Promontory, though no crystalline limestones are here 

 developed, and are doubtlessly coeval with them. Mica slate 

 constitutes the bold inland cliffs on the Hog Bay Eiver, about 

 two miles from its mouth ; and it also forms the base of an 

 unnamed cape, three miles to the west of the mouth of that river. 

 Most of the headlands on the south and west coasts are com- 

 posed of, or are based upon, granite, but whether of metamor- 

 phic or intrusive origin cannot definitely be ascertained ; yet 

 the presumptive opinion is that it forms part of the metamor- 

 phic series. Such formation constitutes Cape AYilloughby, 

 Cape Gantheaume, Pelorus Islet, Cape Du Couedic, Cape 

 Borda, &c. Inland the exposures of mica slate are not frequent, 

 because of the widespread covering of superficial detritus, 

 derived from the mica slate and associated micaceous sand- 

 stones, more or less in place. However, they are sufiiciently 

 numerous to place beyond doubt that the greater part of the 

 island is constituted of this rock. Among the more extensive 

 outcrops may be mentioned those near Birchmore's and White 

 Lagoons, the ridge separating the latter from Murray's Lagoon, 

 and the beds of the Harriet and Stun'sail-boom Eivers. 



Igneous Eocks. — A white granite, apparently intrusive, is 

 quarried near Karatta, on the Stun'sail-boom Eiver. A diorite 

 seems largely to have determined the direction of the elevated 

 ground known as Freestone Hill Eange. 



Miocene. — Forming a low mural cliff at EoU's Point, 

 Kingscote, is a bryozoal limestone, similar in structure and of 

 the same age as that of the cliffs about Oyster Bay, Yorke 

 Peninsula. Among the common fossils, proper to this particular 

 formation of this period, Echinolampas Gamhierensis is note- 

 worthy. The deposit is continued along the shore for about a 



