A guide to Belfast and the counties of Down & Antrim . artfell series, the equivalents of the Bala or Caradoc. 3rd. The black shales at Coalpit Bay, characterized bythe zones of D. acumi>iatus^ D. vesicitlosus, M. gregaritis,and D. come fa, represent in part both the Lower andUpper Birkhill shales, which are paralleled with the LowerLlandoveries. 4th. The grits and conglomerates which immediatelysucceed the latter are of the same age as the Bala series,and occupy a high place in the Middle Silurians. 72 Guide to Belfast. 5th. The black shales and associated flags at Tieve-shilly, near Porta
A guide to Belfast and the counties of Down & Antrim . artfell series, the equivalents of the Bala or Caradoc. 3rd. The black shales at Coalpit Bay, characterized bythe zones of D. acumi>iatus^ D. vesicitlosus, M. gregaritis,and D. come fa, represent in part both the Lower andUpper Birkhill shales, which are paralleled with the LowerLlandoveries. 4th. The grits and conglomerates which immediatelysucceed the latter are of the same age as the Bala series,and occupy a high place in the Middle Silurians. 72 Guide to Belfast. 5th. The black shales and associated flags at Tieve-shilly, near Portaferry, occupy either the extreme top ofthe Middle, or the base of the Upper Silurians, and arethe highest Silurians yet recognised in the north-east ofIreland. The geographical relation of the area under considera-tion to that of South Scotland, and the general direction ofthe strike of the rocks in both districts, would naturally leadto the expectation of a certain degree of similarity betweentheir geological characters. From the foregoing, however,. VERTICAL STKATA, ARDGLASS. it is clear that not only generally, but in detail, do they cor-respond in a remarkable degree. While it would, perhaps,be impossible, owing to the imperfect manner in which thefossil bands are exposed, to unravel the sequence of thevarious bed in County Down from an examination of themalone, the key afforded by the recent researches in theScottish beds has made the subject a matter of are thus enabled for the first time, with someamount of certainty, to arrive at conclusions regarding Stratigraphical Geology. 73 the physical geology of the district. The three graptoliticshale bands and their associated mudstones have beenoverlaid by the grits and conglomerates so conspicuousin the county; all were folded into vast waves, the crestsof which ran in the direction from about north-east tosouth-west. Subsequent denudation completely altered the contourof the district; and, judging from the remnants o
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