Stratigraphical Geology. 73 



the physical geology of the district. The three graptolitic 

 shale bands and their associated mudstones have been 

 overlaid by the grits and conglomerates so conspicuous 

 in the county ; all were folded into vast waves, the crests 

 of which ran in the direction from about north-east to 

 south-west. 



"Subsequent denudation completely altered the contour 

 of the district ; and, judging from the remnants of Carbon- 

 iferous strata at Castle Espie and Cultra, it seems to have 

 been covered by rocks of that age, and to have been again 

 upheaved and subjected to denuding agencies, which prob- 

 ably left it in almost its present state." 



"The north-western boundary of the Silurian area has 

 been subjected to the greatest amount of upheaval, and, as 

 denudation has reduced all to a somewhat uniform elevation, 

 the lowest beds are here consequently most exposed. The 

 Ballygrot beds form the axis of what was the most north- 

 westerly anticlinal ; the black shales of Crawfordsburn, 

 Carnalea, and Orlock Point possibly represent waves of minor 

 importance ; while that at Coalpit Bay seems to have been 

 one of considerable elevation." 



Old Red Sandstone. 



The only representative of the Devonian system in our 

 district is found in a small area round Cushendall. The 

 exposure extends from the caves at Cushendun to Ballyemon 

 Glen, a distance of six miles -the greatest width being three 

 miles. No fossils have been found in the rocks in this 

 district, but on general lithological grounds they have been 

 referred to the Old Red Sandstone, being considered as 

 remnants of the Lake Caledonia basin. On the north-east 

 boundary of the exposure the rocks are found resting on 

 the Archcean schists, and on the south-west they are covered 

 by beds of Triassic age. Finely exposed sections occur 

 along the shore from Cushendall to Cushendun. At the 

 north-end of the exposure at the caves at Cushendun, the 

 rocks consist of a coarse conglomerate with intermediate 

 sandy strata ; the pebbles are composed chiefly of large and 

 rounded blocks of quartz and schist that have been derived 

 from the ancient Archaean ridge to the north-east ; the matrix 



