^8 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 8, 



Carboniferous Limestones of Bristol and along the margins of the 

 South-Wales Coal-field. 



Most of the larger palatal teeth lie in the specular limestone, and 

 in this the oolitic grains are associated with fragments of Brachio- 

 pods, Bryozoa, and Crinoids. 



As the limestone-bands differ in character, some being more shelly 

 than others, some ooHtic, and a third group slightly argillaceous and 

 sandy, they necessarily vary in commercial value, and are used for 

 sundry purposes, among which lime-making and building- stone ap- 

 pear to be chief. The thickest of the oolitic beds has been worked 

 to a considerable extent for decorative purposes ; this is locally called 

 ''jumbles," but is elsewhere known as ^' Clee Hill marble." 



§ 4. But, besides its economic value, this quarry is particularly 

 interesting and important to the palaeontologist, with regard to the 

 fossil fauna of the period, in the comparative abundance of well- 

 preserved ichthyic remains, chiefly Cestraciont teeth and fin-spines. 

 We are indebted to Mr. Weaver Jones, of Cleobury Mortimer, for 

 the preservation of some of the finer and more remarkable of these, 

 especially the great Deltodi, which probably belong to an undescribed 

 species. The attention of another gentleman, Mr. E. Baugh, of 

 Bewdley, has been directed of late years to the fossil contents of 

 these limestones ; and with much assiduity he has collected every 

 fragment of organism which could add to our knowledge. 



The following genera are represented by palatal teeth : — Orodus 

 (specimens of 0. ramosus of unusual size are occasionally met with, 

 — one of those we exhibit exceeds the largest figured by Agassiz), 

 Helodus, Cochliodus, Gladodus, Psammodus, Deltodus (examples of 

 a new species of this form of tooth, of great dimensions, which have 

 been found several times of late, are here figured), and, more rarely, 

 the cusi^ed Pristicladodus Goughii. 



With these, fin-spines of great size are occasionally found asso- 

 ciated. The form most commonly met with is that of a Ctenacanthus ; 

 but the series of tubercles, more or less compressed, which are ar- 

 ranged perpendicular to its length, do not agree with any published 

 figure. Specimens, however, less ornamented, and which appear to 

 be Ctenacanthus brevis, are also met with. , 



No other ichthyic remains, save a few undeterminable fragments, 

 probably of dermal plates, have come under our notice. 



Zones of shells also occur in these limestones, both above and 

 below the beds which contain the fish-fossils, but very rarely asso- 

 ciated with them. These are principally Brachiopods, of which 

 Spiriferoe and llhynchonellce are the most abundant. The species are 

 but few in number ; but an instructive series of intermediate forms 

 — as, for example, those which appear to link together Spirifer cus- 

 jpidatus and >S^. distans — may be collected. 



Among the Rhynchonelloi, R. pleurodon is found in great abundance 

 at the bottom of- the series, though we have met with no instance of 

 its occurrence in the previously laid sandstones. 



TerebraiulcB are nearly, if not quite, absent ; and Discince are only 

 represented by one species — D. nitida. 



