Yol. 55.] THE ASHBOURNE AND BUXTON EAILWAT. 231 



their place being taken by limestone, which is often tufa'^eous ; and 

 thus sections across the beds, only a few yards apart, would vary 

 much in detail. 



III. Crake Low Quarry. (PI. XYIII, fig. 6.) 



Two fields west of the last cutting, and about 100 feet above it, are 

 two old quarries on the south-eastern slope of Crake Low. Though 

 at first sight they seem to be beyond the limits of the ground 

 covered by the present paper, a short description of them may be 

 fittingly introduced, since they throw some light on the sequence of 

 the beds in the last two cuttings. 



The smaller quarry has not been worked for a long time, but the 

 beds in it are similar to those in the larger one. The limestones from 

 the latter were formerly burnt for lime, but now are broken up for 

 road-metal. Porty feet of a very interesting succession of beds is 

 seen. A reference to PI. XYIII, fig. 6, shows them to. consist of 

 limestones, many of which contain volcanic material, separated by 

 thin beds of tuff : they generally contain Productus and encrinite- 

 stems. A limestone is seen to be free from lapilli in one place, 

 while a foot away the same bed is crowded with them ; or a lime- 

 stone free from volcanic sediment in its centre often contains 

 lapilli near its bottom and top surfaces. This is especially the case 

 if there be a layer of tuff or tufaceous limestone above and below it. 



A little more than halfway down the face of the quarry is a bed 

 of coarse tuff, 2 feet thick, with tufaceous limestone above and 

 below it. Erom this tuff I obtained numerous Frodactus-BheWs and 

 a block of igneous rock. The block was very vesicular, and of the 

 Knivetou tj'pe. Some of the layers of tuff intercalated with the 

 limestones and shales in the three cuttings already described contain 

 Productus-%\ie\h, and fragments of large encrinite-stems, and are 

 very similar to the bed of tuff in this quarry. 



Some of the tuff-partings thin out very quickly. In one place a 

 bed of tuff and tufaceous limestone, together about 9 inches thick, 

 thin out in a distance of 6 feet, aud are replaced by limestone free 

 from volcanic ejectamenta. The beds at the bottom of the quarry 

 where the section was measured are of a massive bluish-grey 

 limestone containing foraminifera, and are free from ash. A few 

 yards away they pass into thinner beds, and contain lapilli. Xo chert 

 was found, and very few partings of shale were noticed. It was an 

 examination of this quarry which led me to search carefully for 

 intercalations of tuff in the limestones and shales above the four 

 exposures of ash in the cuttings. The beds dip in a westerly 

 direction into Crake Low, and lie stratigraphically above the 

 Mountain Limestone in the Crake Low cutting. 



We are now in a position to discuss briefly the relations of these 

 beds to those in the two adjacent cuttings. The thick ash in the 

 Highway Close Barn cutting can be traced for a short distance in 

 the fields towards the quarry, and there is little doubt that it is 



