No. 7.] DAWSON — NEW FOSSILS. 411 



PRELIMINARY NOTICE OF NEW FOSSILS FROM 

 THE LOWER CARBONIFEROUS LIMESTONES OF 

 NOVA SCOTIA AND NEWFOUNDLAND. 



By J. W. Dawson, LL.D., F.E.S. 



L—JVOVA SCOTIA. 



The following- are specimens from the collections of Dr. Dawson, 

 made in Nova Scotia and now in the Peter Redpath Museum, 

 and which are either unde.^cribed or serve farther to illustrate 

 species described iu the author's Acadian Geology. 



DiSCITES HaIITTI, DAWSON. 



\Gijrnccras Ilarffl, Acadian Geology.] 



The original description of this species in Acadian Geology 

 (page 311) was based on a specimen showing the outer or body 

 chamber only, and this from its form was at the time (1868) 

 supposed to be referable to the genus Gi/rocwraii. I have, how- 

 ever, recently collected at Brnokfield additional specimens, which 

 throw new light on its structure and affinities. The species may 

 now be described as follows . — 



Form discoidal. apparently with an open umbilicus. Whorls 

 with the dorsal side flat or neai-ly so. This flat space is sepa- 

 rated on each side by a shallow furrow from a strong latero- 

 dorsal ridge, and this by a broader shallow depression from the 

 umbilical ridge, which in some specimens seems to be divided 

 into two by a very slight medial depressed line. Siphuncle 

 small and sub-central, being nearer the dorsal than the ventral 

 side; septa slightly angulated at the latero-dorsal ridge. Body- 

 chamber with slight transverse rugae. Aperture projecting at 

 the latero-dorsal ridue and recedinix at the umbilical ridoe into a 

 deep sinus. Diameter of largest specimen, apparently adult, 2.5 

 centimetres. 



This species may be compared with Nautilus (^Trematodiscas) 

 trisculcatus M. <fe W. (Illinois Report, Yol. II.) or with iY. 

 (^Discites) sulcafus, Sby. As the characters on w^hich the first 

 named authors rely for separating their genus Trematodiscus 

 from Discites are somewhat vague and scarcely apply to the pre- 



