Geology.] 
NATUUAL IIJ STORY. 
571 
about fifty or sixty feet in height was covered with a sandy 
calcareous stone, having the appearance of ‘ concretions 
rising irregularly about a foot above the general surface, with- 
out any distinct ramifications.’ The specimens from this place 
have evidently the structure of stalactites, which seem to 
have been formed in sand ; and the reddish carbonate of 
lime, by which the sand has been agglutinated, is of the 
same character with that of the west coast, where a similar 
concreted limestone occurs in great abundance. 
The western shore of the Gulf of Carpentaria is somewhat 
higher, and from Limmen’s Bight to the latitude of Groote 
Eylandt, is lined by a range of low hills. On the north of 
the latter place, the coast becomes irregular and broken ; 
the base of the country apparently consisting of primitive 
rocks, and the upper part of the hills of a reddish sand- 
stone ; — some of the specimens of which are identical with 
that which occurs at Goulburn and Sims Islands on the 
north coast, and is very widely distributed on the north- 
west. The shore at the bottom of Melville Bay is stated by 
Captain Flinders to consist of low cliffs of pipe-clay, for a 
space of about eight miles in extent from east to west; 
and similar clifis of pipe-clay are described as occurring at 
Goulburn Islands, (see the plate, vol. i. p. 66,) and at Leth- 
bridge Bay, on the north of Melville Island ; both of which 
places are considerably to the west of the Gulf of Carpen- 
taria. 
Morgan’s Island, a small islet in Blue-Mud Bay, on the 
north-west of Groote Eylandt, is composed of clink-stone ; 
and other rocks of the trap-formation occur in several places 
on this coast. 
The north of Blue-Mud Bay has furnished also specimens 
of ancient sandstone ; with columnar rocks, probably of 
clink-stone. Round Hill, near Point Grindall, a promontory 
