1 40 Dr. Fitton on the Geology of Australia. 



the rocks in its vicinity are, dark-gray granite, somewhat ap- 

 proaching to gneiss, with a few specks of garnet ; and a cal- 

 careous, probably concretional stone, inclosing the remains of 

 shells, with cavities lined with crystals of calcareous spar. 



Mount Caledon, on the mainland, west of Caledon Bay, 

 consists of gray granite, with dark brown mica in small quan- 

 tity ; and on the sides and top of the hill " large loose blocks 

 of that rock were observed, resting upon other blocks." 



A small island, near Cape Arnhem, is also composed of 

 granite, in which the felspar has a blueish hue. 



Smaller of the Melville Islands, north-east of Melville 

 Bay*. — A botryoidal mass of ferruginous oxide of manganese, 

 approaching to hematite ; the fissures in some places occupied 

 by carbonate of lime. 



Melville Bay. — Granite, composed of gray and somewhat 

 blueish felspar, dark brown mica, and a little quartz ; contain- 

 ing minute disseminated specks of molybdena, and indistinct 

 crystals of pale red garnet. 



Red Cliffs, south-west of Arnhem Bay; — on the line of 

 the first chain of islands mentioned by Captain Flinders. (See 

 the Map, PI. I., fig. 3.) — Friable conglomerate, of a full brick- 

 red colour, consisting of minute grains of quartz, with a large 

 proportion of ochreous matter. 



Mallison's Island. (Map, fig. 4.) — The cliffs of this 

 island are composed of a fissile primitive rock, on which 

 sand-stone reposes in regular beds. The specimen of the 

 former resembles gneiss, or mica slate, near the contact with 

 granite : the sand-stone is thick-slaty, quartzose, of a reddish 

 hue, with mica disseminated on the surfaces of the joints ; and 

 one face of the specimen is incrusted with quartz crystals, thinly 

 coated with botryoidal hematite. Light gray quartzose sand- 

 stone of a fine grain, with a thin coating of brown hematite, 

 was also found in this island : — And a breccia, consisting of 

 angular fragments of sandstone, cemented by thin, vein-like, 

 coatings of dark brown hematite, was found there, in loose 

 blocks at the bottom of perpendicular cliffs. — The specimen of 

 this breccia is attached to a plate of granular quartz, and may 

 possibly have been part of a vein. 



The shore of Inglis's Island, the largest of the English 

 Company's Range, (2. 2. 2. in the Map,) is formed of flat 

 beds, of a slaty argillaceous rock, which breaks into rhom- 

 boidal fragments ; but the specimen is indistinct. Ferruginous 

 mases, probably consisting of brown hematite, come also from 

 this island. 



* The relative position of the islands and bays on this part of the coast 

 is represented in the enlarged Map, PI. I. 



Astell's 



