[14 



Swanston— Silurian Rocks of Co. Down. 



portions of the black ferruginous bands are exceedingly rich, and have yielded 

 a large series, among which are the following : — 



Diplograptus tricornis, Can: 



,, ANGUSTIFOLIUS, Hall. 



Glossograptus Hincksii, Nich. 

 Clathograptus cuneiformis,Zo#w. 

 Climacograptus Scharenbergi, 

 Lapw. 



,, bicornis, Hall. 



„ „ var. pel- 



tifer, Lapw. 



„ ,, var. tri- 



dentatus, Lapw. 



,, COSLATUS, LapW. 



„ PEREXCAVATUS, 



Lapw. 



Dicranograptus ramosus, Hall. 

 ,, Nicholsoni, Hopk. 



,, FORMOSUS, Hopk. 



Dicellograptus Moffatensis, 

 Catr. 

 i, >> var ' 



DIVAR1CATUS, Hall. 

 DlDYMOGRAPTUS SUPERSTIS, LapW. 

 CCENOGRAPTUS GRACILIS, Hall. 



„ PERTENUIS, LapW. 



„ SURCULARIS, Hall. 



Thamnograptus typus, Hall. 

 Corynoides calicularis, Nich. 

 „ curtus, Lapw. 



Craigavad. —The fossils noted from this locality were obtained from the 

 railway cutting about three-quarters of a mile east of the station. A very 

 small exposure of black shales occur associated with purple shales and grits. 

 The few fossils obtained point to the similarity between the containing beds 

 and those of Ballygrot, of which they are doubtless the south-westerly exten- 

 sion. 



The accompanying table gives a list of the fossils which I have collected 

 from the foregoing localities. The total number is seventy-five species and thir- 

 teen named varieties, in all representing twenty-five genera. This is exclusive 

 of many doubtful forms that have been laid aside waiting better specimens to 

 enable their identification ; also, several that are undoubtedly new, but which 

 are either too fragmentary or badly preserved to warrant a diagnosis. 



The following is a synopsis of those already named, shewing the zoological 

 groups to which they belong : — 



SUB-KINGDOM. 



CLASS. 



Species. 



Varieties. 



Qelenterata. 

 Annulosa. 

 Mollusca. 

 Plants. 



Rhabdophora. 



Crustacea. 



Brachiopoda. 



68 

 3 

 3 



13 



