go Rev. A. Sedgwick on the Geological Relations and 



and in the two outliers in the same neighbourhood. In the last-mentioned place the character of 

 the group is considerably modified, and is partially associated with coarser beds of yellow mag- 

 nesian limestone : it may, however, be described in general terms as a deposit chiefly composed 

 of grey thin-bedded limestone, alternating with thin layers of marl. Most of them are coated 

 over with dendritic impressions ; and, with partial exceptions, they contain much less magnesia 

 than the strong coarse yellow beds by which they are surmounted. On the whole, they make an 

 approach to the external character of the well known beds of Brotherton and Ferry Bridge, 

 though placed at the opposite extreme of the magnesian series. 



Such are the facts upon which is founded that subdivision of the formation 

 of magnesian hmestone which I am endeavouring- to estabhsh. The beds 

 here described, — in their mineralogical character, their relative position, their 

 geological relations, and their organic remains, — present so many analogies 

 with the copper-slate and zechstein of central Germany, that it seems impos- 

 sible not to consider them as all belonging to a common epoch, and as origi- 

 nating- in the simultaneous action of similar causes. 



§ 2. (A.) A deposit of variously coloured Marls, containing irregular beds of 

 Shell Limestone without Magnesia. 



When I stated in a former part of this paper, that there was no charac- 

 teristic exhibition of the inferior red sandstone to tlie south of Barlborough, 

 I by no means intended to assert that, in the whole range between that place 

 and Nottingham, the magnesian limestone rested immediately on the coal- 

 measures. Not far from Nottingham (for example, at Bilborough and Kim- 

 berley) there are some traces of red marl-beds under all the beds of the lime- 

 stone. Marl-pits are also said to have been dug under the escarpment in 

 several places west of Sutton Ashfield ; and some thin beds of a kind of pipe- 

 clay have been found in the same geological position between Barlborough 

 and Clown. These masses of marl and clay would hardly have deserved 

 enumeration, had they not appeared in connection with a much more impor- 

 tant deposit, which is laid bare in the hill side under Kirkby Wood-house; 

 and also with a second similar deposit, which ranging for three or four miles 

 under the escarpment in Derbyshire, is exposed in the side of the road under 

 Glapwell, and in the quarries of Palterton and Bolsover. I therefore now pro- 

 ceed briefly to describe the phaenomena presented at these several localities. 



A rail-road which extends from the Kirkby coal-works towards Mansfield, and cuts through 

 the lower part of the escarpment of the yellow limestone, exposes a series of beds in the follow- 

 ing order. 1, A thick bed of shale. 2. Beds of soft light-coloured slaty sandstone. These two 

 form the base of the hill, and belong to the regular coal-measures. 3. Beds of conglomerate and 

 coarse sandstone, six or eight feet thick. They are of a yellowish-red colour, from the prevalence 



