466 J. W. Jackson— 



Professor Delepine, in an interesting paper recording the presence 

 of the Tournaisian in the Bonlonnais region/ cites the occurrence of 

 D. llangollensis in the massive dolomite of Hiire. Here the species 

 was met with in abundance, along with gasteropods of large size, 

 and certain brachiopods and corals, sufficient to determine the 

 stratigraphical position of the upper part of the Hure dolomite. 

 The horizon compares favourably with the Horizon h of the South- 

 Western Province. 



In Belgium Professor Delepine has recently recorded its occurrence 

 at Florennes, and cites it from three other places : the Gomezee 

 section, west of Florennes (Dr. A. Carpentier), immediately under 

 the massive white Productus cora limestones ; Landelies, at the base 

 of the Productus cora zone ; Sovet, in the Bocq valley, at the top 

 of Sj.^ The position of the limestone containing D. llangollensis 

 at Florennes is thought by Professor Delepine to be equivalent to 

 Sj, or the summit of C,, of the South- Western Province. From 

 these observations it is concluded that in Belgium and in the North 

 of France this fossil occupies a very definite position, ranging from 

 the Productus sublaevis limestones (= upper part of the C, sub- 

 zone of Vaughan) up to the Productus cora oolite (= base of the 

 Sg sub-zone) : it attains its maximum of development and of 

 frequency in the beds between these two horizons, that is to say, in 

 the Sj sub-zone.^ 



It is important to add that an example identified as D. llangollensis 

 has recently been met with in the Vise limestones in a new railway 

 cutting to the north of Vise, along the route from Aix-la-Chapelle 

 to Tongres. This is reported to have occurred with a faima typical 

 of the 1)2 sub-zone. 



Returning to the Derbyshire occurrence of D. llangollensis, 

 attention might be called to the similarity between the limestones 

 containing this fossil at Topiey Pike and the variable basal beds of 

 So in the South-Western Province (as in the Avon Section, 

 Burrington Section, etc.). It is of some interest also to note that 

 Professor 0. T. Jones, on being shown the section recently, was 

 particularly struck with the peculiar character of the limestones, 

 and remarked upon their close identity with certain beds of Middle 

 Visean age elsewhere. 



In my previous note in this Magazine {ante, p. 335) I referred 

 the beds, perhaps rather hastily, to the upper part of Horizon 8 

 (i.e. Si), but Professor Jones is inclined to the view that this is 

 much too low, and has expressed the opinion that the beds should 



^ Delepine, " Note sur la position stratigraphique de la Dolomie de Hure 

 (Boulonnais)," Annates de la Soc. Giol. du Nord, vol xlv, 1920, pp. 142-5 ; also 

 Pruvost & Delepine, " Observations sur la faille d'Hydrequen et sur les couches 

 de base du Carbonifere dans le Bas-Boulonnais," Bull. Soc. Geol. de France, 

 Ser. IV, vol. xxi, 1921, pp. 189-206. 



2 Delepine, op. cit., 1919 (pp. 3-5 reprint). 



^ Delepine, op. cit., 1919 (p. 5 reprint). 



