169 



former, in connection with the Brachiopoda, quite coincide 

 with the specimens forwarded by Mr. Stephens, who gives the 

 locality and horizon as " boulders in a conglomerate of un- 

 known age, near Table Cape, North Tasmania." 



The limited number of fossils from the blocks forming the 

 conglomerate of Table Cape are presented to us wholly as 

 internal casts, and are very difficult to decipher. The matrix, 

 as exhibited in hand specimens, varies to some extent. Certain 

 of the masses are from a bluish-grey fossiliferous limestone, 

 whilst other specimens, equally organic-bearing, are of a 

 yellow or drab colour when weathered, and appear to be more 

 arenaceous, almost passing at times into a grit. 



With few exceptions, the remains are those of Brachiopoda, 

 and, as the most numerous, will claim our attention first. The 

 others are the impressions of a Tentaculites, accompanied by 

 fragments of Crinoid stems. 



The commonest, and at the same time the most interesting 

 fossil met with in the specimens under description, is un- 

 doubtedly a Pentamerus (PI. 2, Figs. 1, 3, 4, 5, 6, 7, and 8), 

 although at first sight its affinities were certainly obscure. 

 There are several specimens in various stages of preservation, 

 some with portions of the shelly matter remaining ; but as the 

 best examples are obtained by fracture of the blocks, 

 entire specimens are seldom seen. The present species 

 have externally a more or less triangular outline, like 

 some varieties of Pentamerus Kniglitiij Sby.*, narrowed 

 towards the beaks and expanded towards the front ; 

 but, unlike Sowerby's species, the ventral valve of the 

 Tasmanian shell is very much deflected at the sides and front. 

 The latter becomes almost cuboidal, and, as it were, geni- 

 culated, thus producing a perpendicular front to the valves. 

 In this character the shells resemble some Rhynchonellse, but 

 not otherwise. The surface was covered by radiating ribs, as 

 in P. Knightii, but in the casts the umbonal or visceral region 

 is almost smooth, or only bearing traces of the muscular 

 impressions, the ribs commencing to show at a little more than 

 one-third from the beak. This is a very characteristic point, 

 and enables us to identify the species throughout the hand 

 specimens, whether in fragments or partially crushed examples. 

 In PI. 2, Fig. 3 and 4, are illustrated a characteristic ventral 

 valve, showing the triangular outline and much deflected 

 sides and front. From the beak forwards proceeds the cavity 

 left by the elongated, strong septum, to which would be 

 attached internally the dental plates, and extending for fully 

 one-third the length of the valve. On each side of it, 

 immediately in the umbonal region, is a more or less smooth 

 space, on which are visible the delicate impressions of the 

 '■ See Davidson's Mon. Sil. Brachiopoda, T. 17, F. 6 and 7. 



