Intraformational Contorted Rocks in the Upper Carboniferous of the Southern Pennines

Abstract

An occurrence in Ireland similar to those described by Mr. Cope from the southern Pennines seems worthy to be placed on record. In the face of the large quarry at Noughaval, Co. Clare (1-inch sheet 123, 6-inch Clare 9) there is a band of contorted shale about nine to twelve inches in thickness lying between beds of undisturbed black shale some three feet above a bed of phosphorite, which in turn is a few feet above the top of the Carboniferous Limestone. The phosphorite is supposed, from the associated goniatites, to lie very near the R and H zones of the Millstone Grit; so that the stratigraphical position of this bed is comparable with that of some of Mr. Cope's examples. The general dip of the beds is about 5° the strike of the intraformational shear-planes being essentially that of the major formations. The feature provided a considerable puzzle before Mr. Cope's explanation was published. A tectonic origin in this case is not, however, altogether convincing, since the regional dips are as a rule less than 50° and much lower than those generally encountered by Mr. Cope. A subsequent attempt at detailed description by the writer was frustrated by the filling.in of the quarry section without previous notice, so that it is no longer visible. There is one photograph, but this is unfortunately not good enough to provide a satisfying record.