Detailed List of Specimens. 139 



Bentinck Island, near Sweer's Island. — A granular com- 

 pound, like sand-stone recomposed from the debris of granite. 

 Brown hematite, inclosing quartzose sand. 



Pisonia Island, on the east of Mornington's Island, is 

 composed of calcareous breccia and pudding-stone, which con- 

 sist of a sandy calcareous cement, including water-worn por- 

 tions of reddish ferruginous matter, with fragments of shells. 



North Island, one of Sir Edward Pellew's group. — Coarse 

 siliceous sand, concreted by ferruginous matter ; which, in some 

 places, is in the state of brown hematite. Calcareous incrusta- 

 tions, including fragments of madrepores, and of shells, ce- 

 mented by splintery carbonate of lime. 



Cape-Maria Island, in Limmen's Bight, was found by 

 Mr. Brown to be composed principally of sand-stone. The 

 specimens from this place, however, consist of gray splintery 

 liornstone, with traces of a slaty structure ; and of yellowish- 

 gray jlint, approaching to calcedony ; with a coarse variety of 

 cacholong, containing small nests of quartz crystals. 



Groote Eylandt is composed of sandstone, of which two 

 different varieties occur among the specimens. A quartzose 

 reddish sand-stone, of moderately fine grain ; and a coarse red- 

 dish compound, consisting almost exclusively of worn pebbles 

 of quartz, some of which are more than half an inch in dia- 

 meter, with a few rounded pebbles of calcedony. The latter 

 rock is nearly identical with that of Simms's Island, near 

 Goulburn's Island on the north coast. 



Chasm Islan d, Winchelsea IsLAND,and Burney's Island, 

 are of the same materials as Groote Eylandt : and sand-stone 

 was found also on the western shore of Blue-Mud Bay. 



On the shore of the mainland, opposite to Groote Eylandt, 

 a little north of latitude 14°, Mr. Brown observed the '* com- 

 mon sandy calcareous stone, projecting here and there in 

 ragged fragments." 



Morgan's Island, in Blue-Mud Bay, north-west of Groote 

 Eylandt, is composed principally oft clink-stone, sometimes in- 

 distinctly columnar. But among the specimens are also a 

 coarse conglomerate of a dull purplish colour, — including peb- 

 bles of granular quartz and a fragment of a slaty rock like 

 potstone : the hue and aspect of the compound being precisely 

 those of the oldest sand-stones. Reddish quartzose sand-stone, 

 of uniform and fine grain. A concretion of rounded quartz 

 pebbles, cemented by ferruginous matter, apparently of recent 

 formation. 



Round Hill, near Cape Grind all, — a prominence east of 

 north from Blue-Mud Bay, was found by Captain Flinders to 

 consist, at the upper part, of sandstone. The specimens of 



S 2 the 



