GEOLOGY OF DERBYSHIRE. 219 



number of quartz pebbles can be derived is really a puzzling ques- 

 tion. The majority of them are in every respect identical with 

 those which, in Warwickshire and the neighbourhood, have been 

 traced to the Lickey hill, and the levels of the country, which they 

 seem to a certain degree to respect, would favour their transporta- 

 tion from that quarter ; but tbey are certainly too abundant to have 

 come wholly from that spot. Hartshill, near Atherstone, and pro- 

 bably some of the harder gritstones of the coal measures and new 

 red sandstone, may have contributed their quota. In the south 

 east corner of Derbyshire, and very abundantly about Chellaston, 

 there is a diluvium of a different character ; and this is the same as 

 that in Leicestershire. It consists for the most part of rounded 

 pieces of chalk and chalk-flints, and contains pebbles and fossils 

 from the oolites and the lias, as also pebbles of coal. Boulders of 

 mountain limestone also occur, but these are found occasionally 

 lying on the surface over all the southern parts of the county, as 

 are also the chalk flints. Pebbles of chalk, oolite, and lias are 

 found nowhere, I believe, north or west of Chellaston. The state 

 of these different materials has the same relation to the distance 

 they have travelled as they have in the gravel of Leicestershire ; 

 but the most remarkable circumstance respecting them at Chellas- 

 ton, is, that patches of this gravel are found interstratified, as it 

 were, with the red marls and gypsum. In the plaster-pits near 

 that place, there is thirty or forty feet of red marl exposed, resting 

 on a thick mass of gypsum. The red marl is regularly bedded, per- 

 fectly horizontal, and contains regular bands of fibrous gypsum and 

 lines of lenticular shaped masses of it lying in the plane of the 

 beds, quite conformable to the gypsum below, and the whole, to all 

 appearance forming one connected mass which was deposited with- 

 out any breach of continuity. At various parts of the red marls, 

 however, and frequently below the whole, on the thick bed of gyp- 

 sum, lie patches of this gravel, a foot or two in thickness, contain- 

 ing pebbles and fossils of the lias, the oolites, and the chalk forma- 

 tions, all of which are of later date than the red marl itself. Not- 

 withstanding the regularity of their appearance, therefore, it would 

 be necessary to suppose this particular mass of red marls to be a red- 

 integrated portion formed of the broken materials of other beds, and 

 deposited along with the diluvium. While examining the materials 

 thus singularly associated, however, one of the workmen mentioned 

 the term " pot holes ;" and on my enquiring what he meant, I 

 found that over or near to one of these patches of gravel, there was 

 frequently a " pot hole ;" that is, a soft place in the marl, through 



