342 Joseph Lucas — 27^6 Permian Beds. 



stone. Thi-s too is in the same bed, whicli, as far west as eight 

 miles west of Harrogate, near Fewston, is conspicuotisly red, 

 coarse, and partly unconsolidated. There the colour is quite its own. 

 North of Eipon the base of the limestone is seen near 



1. Galphay Bridge, over the Laver, where it is separated from the underlying un- 



coloured coarse grit by a few feet of Permian flaggy sandstones and a few 

 intermediate bands of red and grey marls. 



2. Near Quarry House, Sleningford, pale yellow limestone is separated from the 



uncoloured grits below by a few feet of blue flaggy limestones with 

 Frodiicta horrida. 



3. At Crakehall High Mill, pale yellow limestone passes over a few feet of pale 



yellow magnesian osnglomerate, which rests on grey marl, three feet, and 

 that on red marl of which only two feet were seen. Here the colour is 

 not derived from the limestone, as the grey marl is the upper one. 



Thus of fifteen sections along the base of the Magnesian Lime- 

 stone, for a distance of about thirty-two miles measured straight, 

 not one exhibits purple grit immediately under the Magnesian Lime- 

 stone. Four clean sections .show limestone resting on uncoloured 

 grits. In one case only, where purple grit is seen in the same 

 quarry as Magnesian Limestone, there is an intermediate bed of red 

 marl. All the other sections show uncoloured beds close below the 

 limestone. 



Under any circumstances, only one and the same bed is found to 

 be purple, and this one in the limited area over which it maintains 

 its colour with any constancy is frequently of a bright red. Far 

 down in the Millstone-grits there is another thin but very often 

 bright red or ochreous bed, which I have mentioned before as the 

 liedscar grit, and Mr. Ward quotes another under Bradford Moor, 



The purple colour in question is so exactly that of the Permian 

 marls, that taking into account the number of times that the lime- 

 stone has failed to impart any colour to the beds below it, and that 

 it cannot be proved to have done so in one single instance, I cannot 

 avoid the .conclusion that the date at which the Plompton ^rit re- 

 ceived its purple colour was during the deposition of the earliest 

 Ted sediments below the limestone, and that the carbonate of iron 

 sank into the Plompton grit from Permian waters, and not from 

 subsequent infiltration from (colourless limestone. In no section 

 where I have seen weathered Magnesian Limestone in quarries has 

 it been red, which the peroxidation of its iron should have made it, 

 if Mr. Ward's supposition were true. Subsequent overlap may have 

 brought the limestone to rest against uncoloured Carboniferous rocks. 



I would extend the remark to all rooks which underlie red rocks, 

 and are stained red by infiltration, that the infiltration took place 

 when the earliest red beds l5^ng rupon liiem were being deposited, 

 and that the vehicle was the same as that which conveyed tiie colour- 

 ing matter into the beds above. Thus if sediments are about to be 

 thrown down in waters charged with carbonate of iron upon a bed 

 of porous rocks, I see nothing to prevent carbonate of iron froni 

 being carried into the latter as well as into the former ; when under 

 exposure to favourable circumstances both would appear red. In 

 the explanation of the quarter sheet, 93 SW.,^ the lower limestone is 

 ^ Mems, of tlhe GeoL Surv, of Ea^aiad and Wales. 



