﻿Vol. 64.] 



CAEBONIFEKOirS ROCKS AT LOUGHSHINNY. 



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bedding - planes of the 

 limestone-bands and the 

 whiteness of the calcite. 

 Phacoidal or ' augen '- 

 structure in rocks is usually 

 the result of compression. 

 These structures, however, 

 have been produced by 

 tensile and torsional 

 stresses that have opened- 

 out these ' augen '-cracks 

 in the rocks, especially on 

 the anticlines, during the 

 folding of the beds, the 

 cavities being subsequently 

 filled up with calcite. 



The Loughshinny Black 

 Shales and the underlying 

 Posidonomya - Limestones 

 in the clifi's at Loughshinny 

 strike across a sandy shore 

 towards Loughshinny 



Harbour, where there is 

 a good exposure of folded 

 limestones associated with 

 laminated argillaceous and 

 calcareous shaly beds pos- 

 sessing much the same 

 character as the Posidono- 

 ^7Z2/a-Limestones at which 

 they strike. Fossils are, 

 however, much less abun- 

 dant at Loughshinny Har- 

 bour, and I did not meet 

 with any of the bands of 

 Posidonomya Becheri which 

 are characteristic of the 

 beds opposite. There may, 

 then, be some justification 

 for the fault which is 

 situated at this spot on the 

 Geological - Survey map, 

 but for which I could 

 see no stratigraphical evi- 

 dence. At the harbour 

 (fig. 12) the beds are 

 folded into numerous steep 

 anticlines and synclines, 

 the dips being sometimes 

 reversed. Higher beds 



