498 B. Clark — Silurian Fossils of North-East Ireland. 



completion of the one-inch Geological Map of Ireland enabled the 

 revision of work done in the earlier stages of the Survey's existence 

 to be undertaken, and in this revision the North-East Silurians 

 vsrere amongst the first dealt with, and I was detailed to search the 

 most promising localities for fossite, and to zone the beds in which 

 they might occur. 



This work was proceeded with until not only the North-East area 

 but the Southern Silurian districts also were gone over; and a 

 comparison of the old series of maps and the revised editions which 

 h^>T*'» been published within the past few years will show that the 

 results of the collections made have necessitated very considerable 

 alterations in the original mapping. 



Taking Coalpit Bay, Donaghadee, as a starting-point, this prolific 

 though circumscribed little area, afforded a key to the vast proportion 

 of the Silurian beds which with slight interruption extend south- 

 wards to the Atlantic on the Waterford coast ; and although in few 

 other localities was the same wealth of fauna of different horizons 

 met with, it was interesting to recognize in numerous new localities 

 the occurrence of forms which enabled a ready recognition of the 

 exact position of the beds, most of which were typically represented 

 in the regular sequence of Coalpit Bay. 



As some time must elapse before revised explanations to the new 

 editions of the maps will be forthcoming, brief notices of new or 

 hitherto unrecorded species, gaps filled up, and new localities may 

 be interesting and useful. 



In the district covered by Mr. Swanston's paper it will be 

 sufficient to mention a couple of localities, new or hitherto unreferred 

 to. First I would mention a section cut through by a small stream 

 at Lissan, near Saintfield (Sheet 37), from which a number of 

 specimens indicative of Lower Hartfell (Caradoc) beds were 

 obtained ; these were mostly in a state of excellent preservation, and 

 amongst other species were the following : — 



Diplograptus foliaceus. Dicellograptus elegans. 



,, mucronatus. „ Forchammeri. 



,, truncatus. „ Morrissi. 



Climacograptus Scharenbergi. „ Moffatensis. 



Zeptograptus flaccidus. Dicranograptiis ramosus. 



Pleurograptus linearis. Corynoides calcularis. 



Glossograptus Sincksii. SipJionotreta micula , 



The second locality is a small quarry in Holy wood Glen (Sheet 29), 

 which yielded a number of species characterizing this locality as the 

 Glenkiln horizon (Upper Llandeilo) ; principal amongst the forms 

 which occur here in easily recognizable condition being — 



Coenograptus gracilis. Climacograptus bicornis. 



,, circularis. Dicellograptus inter tus. 



,, pertenuis. „ sextans. 



Thamnograptiis typhus. „ Moffatensis. 



Glossograptus ITincJcsii. Dicranograptiis ramosus. 



Climacograptus Scharenbergi. 



