Notices of Memoirs — Derbyshire Limestone Fauna. 467 



out when the centre line of the syncline is approached. There is no 

 evidence to suggest any general eastward rise of the Barnsley Seam 

 within the area plotted on the map. (The eastern boundary of the 

 map is through Thorn e and Retford.) 



4. By the plotting of the contour-lines on Bartholomew's layer- 

 coloured half-inch contour map, the interdependence of underground 

 structure and topographical relief in the area of the exposed coalfield 

 has been well brought out. Over the whole coalfield most of the 

 ridges are of escarpment form and are elongate along the line of 

 strike, but from the map it becomes evident that wherever the strike 

 of the Barnsley Bed shows a change of direction, there the escarpment 

 ridges are found upstanding above their average height, and this 

 "whether they form the arches or lie in the troughs of the folds. 



From his experience of the application of the contour method to 

 the study of the tectonics of the Barnsley Bed, the author suggests 

 that the method is of peculiar usefulness in coalfield work. He offers 

 this preliminary account of the results of his work in Yorkshire in 

 the hope that workers on the western side of the Pennines may take 

 up the method and use it in the further investigation of the many 

 and difficult problems of geological structure presented by the ' Back- 

 bone of England '. 



(2) A Brief Criticism of the Fauna of the Limestone Buds at 

 Treak: Cliff and Peakshill, Castleton, Derbyshire. By 

 Henry Dat, M.Sc 

 fMHE author put forward some observations on a collection of some 

 J_ three hundred species of Carboniferous Limestone fossils from 

 the localities Treak Cliff and Peakshill, Castleton, and embracing about 

 one hundred species of Brachiopods and Corals. The beds at both 

 places may be referred to the ' Brachiopod beds ' of Sibly (Q.J.Gr.S. 

 1908), which are allocated by him to sub-zone D 2 — the Lonsdalia 

 sub-zone. The present list of species presents some features of 

 considerable interest bearing on the value of certain types as zonal 

 indices. Reference is made to Vaughan's paper on the Bristol area, 

 where it is indicated that amongst the Brachiopod groups confined to 

 the Tournaisian in that area are the following: Productus cf. Martini, 

 Leptena analoga, Schizophoria resupinata, Rhipidomella aff. Michelini, 

 Spiriferina octoplicata, Syringothyris cuspidata. Two of these, it is 

 noted, Spiriferina octoplicata and Schizophoria resupinata, are sub- 

 zonal indices, and each with its maximum in its sub-zone. The list of 

 Castleton forms from well up in D, now presented, includes all the 

 above-mentioned Brachiopod groups. Syringothyris cuspidata and 

 Spiriferina octoplicata are fairly abundant at both Treak Cliff and 

 Peakshill, Schizophoria resupinata is extremely abundant at both 

 places, Leptena analoga is abundant, whilst Productus cf. Martini 

 and Rhipidomella Michelini are rare. 



Passing to the coral fauna, the genus Zaphrentis appears in the 

 Castleton list, i.e. one of the two genera of Corals confined to the 

 Tournaisian in the Bristol area and not extending into the Visean. 

 The genus, though not very abundant, is represented by several 

 species. In addition, the genera Michelinia and Amplexus, 



