538 [Proc B.N.F.C., 



inspection. As a local collection they are of the greatest 

 interest, and very fully illustrate the fossil contents of the rocks 

 in the locality. They are chiefly of the Cretaceous or chalk 

 formation, of which the section on the slope of Benbradagh, 

 over the town of Dungiven, is the most western escarpment in 

 Europe, and represents a formation that occurs in a more or 

 less coniinuous band from thence through Europe into 

 Palestine. The quarries on Benbradagh are the most fossili- 

 ferous chalk rocks we have in the North, and the variety of the 

 species is very remarkable. On this point, however, the 

 number of species of fossils or plants credited to any locality 

 depends very much on the zeal and skill of the collector, 

 qualities that distinguish Mr. Thomson, and hence his collection 

 is as remarkable for the number and variety of the species as 

 for the great number of individual specimens of some species. 

 The Sponges, Echinodermata and Cephalapoda are exceedingly 

 abundant, and many of the less known forms elsewhere are 

 numerous here. 



Mr. Thomson was good enough to accompany the party up 

 to the quarries on Benbradagh, where a considerable number 

 of specimens were collected. In ascending the hill from the 

 plain below the Carboniferous Triassic and Cretaceous rocks 

 were traversed, and all were capped as at Cave Hill, with the 

 Basaltic rocks. A walk of about a mile on the crest of the hill 

 enabled the party to reach, by a gradual slope, the highest 

 point of the mountain 1,536 feet high. 



From this point there is a most extensive view, and as the 

 atmospheric conditions were most favourable every feature of 

 the grand panorama was distinctly visible, Errigal and Muckish 

 in the North- West of Donegal, Knocklayd and Sleamish in 

 Antrim, the Mull of Cantyre, and the mountains of Down and 

 Tyrone ; while the wide stretch of country between, with 

 towns, hamlets, mansions, and farms, looked like a carpet of 

 green and an unbroken flat. The details of ridges and hollows, 

 hills and valleys, were all subdued in consequence of the 

 superior elevation of the point of observation. 



