BY JOHN MITCHELL AND W. S. DUN. 267 



that he had identified this species in a collection of fossils from New South Wales 

 whicli had been sent to the Woodwardian Museum of Cambridge University by 

 Clarke in 1844 for description.* 



In 1877 its presence is noted by Prof, de Koninckt from Kempsey. and the 

 banks of the Murrumbidgee [Devoniair] . With regard to the Kempsey locality 

 there is considerable doubt, the formations in that area being of Upper Palaeozoic 

 age. In 1888 the species was reported from the Bowning Beds.l In 1880 R. 

 Etheridge, Jr., recorded A. reticularis from Bombala, and the variety aspera froiii 

 Collins Flat.^ 



Normal specimens of this fossil from the Bowning- Yass Beds, exclusive of 

 their foliated margins, appear to be rather smaller than the European species. 

 The dimensions of one of the largest specimens from these beds are^length and 

 width, 20 mm., depth 11 mm. Judging from the figures of A. reticularis in 

 Davidson's British Brachiopoda, it would apjsear that adult British species usually 

 exceed an inch in length and width, and are more gibbous than our forms. The 

 pedicle valves of our specimens too seem less convex in the umbonal region, and 

 more concave laterally and anteriorly. Some specimens from Wellington Caves, 

 N.S.W., have been obtained of relatively large size, their length and width ex- 

 ceeding 43 mm. without the fringe, with a thickness of 26 mm. In these speci- 

 mens the radial ribs are coarse, and the marginal sinus in front deep and tongue- 

 like, but, except for their unusual size, their external and internal features, as far 

 as they are revealed, are quite typical of the normal A. reticularis. 



In tlie upper beds of the Bowning Series, a form occurs, possessing features 

 which would place it about midway between A. aspera and A. i\eticularis, and al- 

 though these features are unvarying in all the specimens of it that have come 

 under our notice, we deem it undesirable to separate it from the type form at 

 present. Vide PL xvi., fig. 13. 



The stratigraphical range of the species in the Bowning Series extends practically 

 from base to summit ; but it is most abundant in the lower beds of the series espe- 

 cially in those of Hatton's Corner and the limestones of Limestone Creek, Silver- 

 dale. Its associates in these beds are Barrandella linguifera var. wilkinsoni Eth., 

 Bhizophyllum interpunctatum de Koninck, Encrinurus mitchelli Foerste, Bronteus 

 jenkinsi E. and M., etc. 



Loc. and horizon. — Hatton's Corner, Yass River, Parish of Y'ass, County Mur- 

 ray; Limestone Creek Parisli of Derrengullen, County King; Bowning Creek, 

 etc . , Parish of Bowning, County Harden . Upper Silurian — Wenlock or Bar- 

 rande's etage E of Bohemia; and in the upper part of the. Bowning Series pro- 

 l)ably passing into Devonian. 



Atrypa erectirostris, n.sp. (PL xv., figs. 10, 11; PI. xvi., figs. 17, 18.) 



Shell subdiscoidal when the fringe is attached in mature specimens; radial 

 striae numerous, fine, strongly arcuate laterally and dichotomous at more or less 

 frequent intervals. Pedicle valve moderately convex at the umbonal region, con- 

 cave laterallj', and at front margin only mildly sinuate, umbo inconspicuous, beak 

 erect, high, acutely-pointed, laterally supported by strong divergent umbonal 

 ridges. Aperture circular, the under half enclosed by the deltidial plates, false 

 area conspicuous, hinge line wide, undulating; cardinal angles high and rounded. 



•Sed. Form. N.S. "Wales, 1878, p.l.5.j. 

 +Mem. Geol. Surv. N.S.W., Pal. No. (i, 1898, pp. 77-78. 

 JMitehell, Proc. Aust. Assoc. Adv. Sci., i., 1887 (18S8), p. 293. 

 SJour. Proc. Eoy. Soc. N.S.Wales, xiv., 1880, p.216. 



