Geological Olservalions. 187 



slate, and that a few thin beds of transition limestone occur iu 

 the slate. These, as far as 1 have been able to collect, are the 

 only instances of the occurrence of transition limestone in Eng- 

 land : it is yet to be ascertained, whether the primitive or fo- 

 liated limestone anywhere exists in this country. The only pri- 

 mitive districts in England are Cornwall, the Isle of Man, and 

 Xorth Wales. The two former have now been minutely examined. 

 \vithout anv locality having been given of tlvis rock: — the proba- 

 bilitvof its occurrence is therefore confined to North Wales. 



Having made tliese remarks upon the classification of the 

 limestones in England, I proceed to offer Some observations on 

 the red ground, in order to show that much confusion prevails 

 in regard to the beds that properly constitute this formation. If 

 we attend to the general succession of rocks in England, we ob- 

 serve a striking conformity to the truly admiral/le system of Wer- 

 ner. In Cornwall, and in the Isle of Man, we have granite and 

 clay-slate; and in North Wales, according to Mr. Aikin (see 

 his Tour through North Wales), we have granite, mica-slate, 

 hornblende-slate, serpentine, and other primitive rocks. In the 

 above-mentioned districts, upon the primitive rocks rest thos<» 

 of the transition formation, consisting of gray wacke, limestone, 

 and gray wacke-slate, which, however, sometimes, as at Mal- 

 vern, in Cumberland, &c. are found unassociated by the older 

 rocks. — Upon the transition series, as has been well remarked 

 bv Dr. Prichard in the paper above referred to, repose in almost 

 every district the members of the first flostz formation, the old 

 red sandstone and mountain limestone, upon one of which all 

 the coal formations in England, with the exception of that ia 

 Derbvshire, seem to recline. — Independent of these formations, 

 an extensive series of horizontal strata is observed in many part* 

 of England to cover the coal-fields, and the mountain limestone 

 and red sandstone by which they are inclosed. Of this class of 

 strata, the lowest, or those immediately covering the coal-fieldq, 

 and their inclosing strata, are the beds of what is called the Red 

 Ground. Above these occurs the lyas limestone, which is fol- 

 lowed by several varieties of oolite, and then again by the chalk. 

 From this statement it is obvious, that the red ground or rocU 

 inarl must be of later origin than the coal-measures or the first 

 floetz formation. But such have been the inaccuracy and con- 

 fusion of those who have had the best opportunities of ascertain- 

 ing the true nature of the red ground, and its relative position 

 with other formations, that not only members of the floetz but 

 even of the transition series have been referred to this formation. 

 Thus, Mr. Farey in his account of Derbyshire, when enume- 

 rating the beds, or, as he calls them, the products of the red 

 ground, mentions t^fter gypsum and sandstone strata, sieuite and 



roof 



