T. Mellard Reade — Physiography of the Lower Trias. 155 



CEPHALOPODA. 



Orthoceras, sp. 

 A small fragment half an inch long, too imperfect to determine, 

 showing a central siphuncle and seven of the septa. 

 Locality. — Irwin River, Victoria District. 



Discites, sp. 



A young example, somewhat crushed, of the type of "Discites 

 [Nautilus'] Omalianus, de Koninck (Descr. des Anirn. Foss. du Terr. 

 Carb. de la Belgique, Suppl., 1851, p. 711, pi. lx. figs. 3, a-c). 

 The specimen has the test preserved, and its ornaments consist of 

 fine thread-like spiral lines crossed by very numerous, close-set 

 transverse lines; the septa moderately distant, i.e. about two lines 

 apart upon the peripheral face, where the transverse diameter is four 

 lines. The greatest diameter of the fossil is 1 inch 2 lines. 



Locality. — Irwin River, Victoria District. 



EXPLANATION OF PLATES VI. and VII. 



PLATE VI. 



A fine group of specimens of Spirt/era lata (McCoy), in Carboniferous Sandstone 



from the Lyons Paver, a tributary of the Gascoyne River, West Australia. 



PLATE VII. 



Figs. 1, la. — Spirifera Hardmani, Foord, sp. nov. Exterior of ventral valve, and 



(In) interior of ventral valve, showing hinge-area. 

 Fig. 2. — Spirifera Musakheylensis (Davidson), var. Australia, Foord, var. nov. 

 Fig. 3. — Athyris Macleayana (Etheridge, jun.), and see also woodcuts in text. 



Figs. 1, 2, and 3, all from the Carboniferous of the Gascoyne River. 

 Figs. 4 and 4a. — Product us tenuistriatus (de Verneuil). 

 Fig. 5. — Productus subquadratus (Morris). 

 Fig. 6. — Productus undatus (Defrance). 

 Figs. 4, 5, and 6 all from the Carboniferous of the Irwin River, Victoria District. 



II. — Physiography of the Lower Trias. 

 By T. Mellard Reade, C.E., F.G.S. 



THE origin of the Lower Trias is evidently a question of interest 

 to the readers of the Geological Magazine. Professor Bonney, 1 

 in an article, to the tone of which no exception can be taken, 

 criticizes the view which I have ventured to put forth, 2 and very 

 properly supports his own. It would be impossible and a waste of 

 paper and type for me to traverse all his statements, as in many 

 cases my reply would amount to little more than a reproduction, in 

 a different form perhaps, of the arguments already made use of. 

 There are, however, one or two points on which I should like to 

 express myself, and there are some misconceptions that require 

 clearing up. 



Professor Bonney holds pretty strongly to the view that the 



pebbles of the Bunter have come from Scotland, and says, " I 



entirely fail to see any improbability in regarding the Pennine 



Chain as an upland which separated for a time the valleys of two 



1 Geol. Mag. Feb. 1890, pp. 52-5. 2 Ibid, Dec. 1889. 



