158 THE VICTORIAN NATURALIST. 



flint implements and weapons. The ground around my encamp- 

 ment was extensively strewn with flakes and chips, showing that 

 the locality was one to which the natives had had recourse for 

 stone weapons for ages. Other volcanic areas were to be found 

 east and west of Port Darwin, and at the head of the Victoria 

 and Fitzmaurice rivers. Isolated hills, which may have been 

 points of ejection of volcanic material, diversify these areas, 

 which are always more fertile than the surrounding country, with 

 black soil and nutritious grasses. Fisher and Stevens' station, 

 at the head of the Victoria River, is on such a volcanic tract. 



Besides these trap-rocks, all through Arnhem's Land one 

 meets continually with an outcrop of a blue, compact, particularly 

 hard, igneous rock, which runs parallel with the ranges of crys- 

 talline schists. It is probably an ancient rock, for it stands out 

 in lines of flags six or eight feet high like gravestones, mostly in 

 the valleys or flats at the base of the hills. There are also many 

 dykes of basalts and dolerites with small porphyritic crystals of 

 labradorite, cropping out in the granite, pegmatite, and crystalline 

 schists. 



(To be concluded in our next.) 



ON VOLUTA UNDULATA AND ALLIED SPECIES. 



By Professor Ralph Tate, F.G.S. (Hon. Member). 



(Read before the Field Naturalists' Club of Victoria, \2th 

 November, 1888.^ 



This very beautiful and very distinct volute, singularly remarkable 

 for its undulating colour-lines, has been known by figure and 

 description for nearly three-quarters of a century; and though 

 frequently described and illustrated up to the last three or four 

 years, yet the conchologists of the country which produces it 

 actually do not know it correctly. 



Lamarck figured it in "Ann. du Mus." vol. v., p. 157, t. 12, fig. 

 I, and it was described by him (" Animaux Sans Vert.," vol. vii., 

 part i., p. 345, 1822) from specimens obtained by Peron, the 

 naturalist to the French Exploring Expedition, under the com- 

 mand of Captain Baudin (1800-4), in Bass Straits and Maria 

 Island. The locality in Bass Straits is probably King Island, as 

 the exploring ships sheltered there for a considerable number of 

 days. 



Again, had we any doubt about the identification of the 

 Lamarckian species, Quoy and Gaimard's interpretation of it 

 should set us right. The admirable figures of the shell and 

 animal of this species given by these authors are of specimens 

 collected by them at Western Port, in Victoria. 



During the last twenty-five years an allied species has 



