490 J. W. Jackson and J. K. CharlesivortJi — 



limestones is not altogether clear ; they are later than the Caldon 

 Humerosus beds, and are faulted down along with the quartzose 

 conglomerate. They appear to us to represent a portion of the upper 

 part of the Lonsclalia subzone, and to be related to the fossiliferous 

 limestones of the churchyard at Cauldon to the north, ^ which are 

 almost certainly upper D2. The somewhat similar faulted block of 

 fossiliferous limestones opposite the Red Lion Inn, about half a mile 

 south, is probably of the same age. 



The horizon of the Humerosus beds of Caldon Low has been the 

 subject of some dispute during recent years. In 1908 ^ they were 

 tentatively assigned by Dr. Sibly to the upper part of the Lower 

 Dihunoiohyllum zone, Di. This position received strong confirmation 

 in 1918 by Mr. L. M. Parsons' researches in Leicestershire (at 

 Breedon Cloud and Breedon-on-the-Hill).^ Other workers, including 

 the late Dr. Wheelton Hind,"* have definitely assigned them to the 

 base of the Visean, viz. C-Sj. A full discussion of this important 

 problem cannot be entered upon here, but must be reserved for a 

 future paper dealing with the horizon of the Humerosus beds of 

 Dove Dale. A preliminary article on this area, by one of the present 

 writers, has already appeared in this Magazine.'^ The Dove Dale 

 limestones are of the " Brachiopod Bed " type, and their faunal 

 characteristics suggest that their stratigraphical horizon is nearer 

 Do than Di. We are inclined to regard the Caldon Low limestones 

 with Productus humerosus as a more normal, but less fossiliferous, 

 development of the Dove Dale series. The species at Caldon is not 

 common throughout, but occurs only in well-defined beds, associated 

 with a few other fossils, including two or three interesting forms of 

 corals, which require further study. 



Petrography of the Conglomerate. — Want of space prevents a lengthy 

 discussion of the various constituents of the quartzose conglomerate, 

 but readers are referred to the paper published in February, 1919 

 (op. cit., p. 60), for the main details. The whole assemblage, in our 

 opinion, contains nothing of later date than the Carboniferous 

 Limestone. 



As pointed out in the earlier paper (op. cit., pp. 62-3), a rolled- 

 shell and limestone-pebble conglomerate forms a striking feature 

 along the boundary of the Midland Limestone massif on its north- 

 western and western sides. In places this conglomerate contains 

 a fair amount of well-rounded quartz, some pebbles being of large 

 size.'' From closer study of this marginal feature we have no 



1 Geol. Mag., Vol. LVI, 1919, pp. 61-2. 



2 Quart. Journ. Geo). Soc. vol. Ixiv, 1908, p. 44. 



3 Ibid., vol. Ixxiii, 1918, pp. 94-100. 



^ Geol. Mag., vol. LV, 1918. p. 480 ; Vol. LVII, 1920, p. 78. 



5 Ibid., Vol. LVI, 1919, pp. 507-9; see also Sibly. ibid., Vol. LVII, 1920. 

 pp. 20-2. 



^ We have seen specimens in W. F. Holroyd's collection and possess others 

 from similar beds near Wetton, Staffs. See also Trans. Manch. Geol. Soc, 

 vol. XXV, 1896, pp. 124-5. 



