14 



two miles wide) on the north, the latter extending in a southerly 

 direction, and separating Roebuck from Gantheaume Bay. The 

 coastline exhibits low, steep cliffs of red sandstone at the base, 

 12 to 20 feet high, and overlain by sand or arenaceous clays, 

 from 40 to 80 feet in thickness. The former, however, retreat 

 sometimes for miles inland. The sea margin at the head of the 

 bay is covered by mangrove {Avicennia officinalis, L.), succeeded 

 by open grassy flats several miles wide, gradually passing into 

 gentle rises and undulating hills (covered more or less thickly 

 with scrubby vegetation) and more elevated grass lands. Roebuck 

 Ray is, and has been for many years, one of the chief harbours 

 of the pearling fleets, and has become the starting place of the 

 AVest Australian submarine cable, as well as one of the ports of 

 approach to the Kimberley gold-diggings, hence a small township 

 has sprung up since 1890. The climate is extremely hot and 

 dry, the maximum temperature being above 100^" F. in the shade 

 for many months in succession, and sinks rarely as low as 60° F. 

 During the three years 1889-91 the rainfall was extremely 

 scanty and insuflicient, and appears to be uncertain, intermit- 

 tent, and of short duration usually, though sometimes is heavy 

 and accompanied by violent thunderstorms. 



As informed by Sir Ferdinand v. Mueller, the locality had 

 remained botanically almost unknown, notwithstanding its early 

 discovery. Messrs. King and Gregory collected some plants 

 there, but the former only near the coast, while most of the 

 specimens of the latter proved unsatisfactory. Thus it is almost 

 the first time that the locality has been extensively examined in 

 regard of its botany, and my best thanks are due to my son for 

 spending much of his scanty leisure in the collection and prepar- 

 ing of the specimens which form the subject of this paper, not- 

 withstanding his other arduous duties and the unfavorable nature 

 of the climate. There are enumerated 143 species (besides one 

 wholly undetermined) comprised in 100 genera and 44 orders. 



SYSTEMATIC LIST OF ROEBUCK BAY PLANTS. 



[The months are those attached by the collector, and denote 

 the flowering season, unless stated otherwise.] 



Capparideae. 

 Cleome tetrandra, Banks. January, 1890. 



viscosa, L. July, 1889. 



Capparis lasiantha, R. Br. August, 1890. 

 spinosa, L. July, 1889. 



Violaeeae. 



Hybanthus suflruticosus, F. i: M. December, 1889. 



