320 Cosmo Johns — Carboniferous Beds, Ingleton. 



find stride. Finally, it may be well to add that no attempt bas been 

 made to give an exhaustive list of the rocks represented by fragments 

 in the breccias at any localitj', and that while all the exposures 

 described are in the breccia and conglomerate e^, those to the north 

 are usually on a higher horizon than those to the south, owing to the 

 prevailing north-easterly dip. 



IV. — On the Cakboniferous Basement Beds at Ingleton. 



By Cosmo Johns, M.I.Mech.E., F.G.S. 



DURING the Spring meeting of the Yorkshire Geological Society 

 at Pateley Bridge it was suggested that, as a first step towards 

 the zonal classification of the Lower Carboniferous rocks of 

 Yorkshire, it would be desirable to determine the horizon of the 

 basement beds at Ingleton as compared with the Avon sequence. 

 As the Yorkshire Naturalists Union had arranged a meeting at 

 Ingleton for May 12-14:th, the geological route was arranged so as 

 to include as many exposures of the basement beds as possible. 

 The result of the observations made then and during subsequent 

 visits is the subject of this communication. 



The district investigated is so well known and has been described 

 or noticed by so many workers that a list of references would be 

 out of place in a short note like this. It does not appear that any 

 previous attempt has been made to determine the exact horizon of 

 these particular beds. They are cut ofi" towards the south by the 

 North Craven Fault, but are well exposed at Norber, on both sides 

 of Ingleton Dale, and also in Thornton Dale below Thornton Force. 

 The beds are best seen in Ingleton Dale, and can be easily traced 

 by the line of springs which follow approximately the 800 foot 

 contour-line on both sides of the valley. The structural features are 

 simple ; the basement beds follow the uneven lines of the pre- 

 Carboniferous land surface. These older rocks are folded and 

 denuded, so that they now stand almost vertical with a strike 

 averaging north-west and south-east. A series of later folds along 

 an east and west axis probably causes a repetition of the beds, and 

 all that can be said at this stage is that we have here probably 

 a complex of rocks older than is generally considered. 



Above the basement beds come the Great Scar Limestone, then the 

 Yoredale Series, while a capping of Millstone Grit appears on the 

 highest hills. These beds lie almost horizontal, are practically 

 undisturbed by faults, and, except for an almost imperceptible dip 

 to the north-east, remain just as they were deposited. The basement 

 beds themselves consist of a conglomerate of varying coarseness, 

 replaced here and thereby pure limestone. The conglomerate generally 

 appears in the hollows of the pre-Carboniferous floor, while the 

 crest of the eminences are often covered with limestone bands free 

 from included pebbles. Quartz pebbles of all sizes are abundant, 

 and layers of conglomerate are often separated by limestone bands. 

 At the foot of Norber, where 25 feet of basement beds appear, the 



