BRITISH ISLES. 13 



divisions. The highest is singularly constant in character and thick- 

 ness ; the lowest varies a good deal ; the middle division is very change- 

 able, its beds thin out and replace each other. The author supposes the 

 floor on which these deposits were laid down to have been uneven, and 

 that the grit filled up the hollows. W. T. 



Green, Prof. A. H. On the Variations in Thickness and Character of 

 the Silkstone and Barnsley Coal Seams in the Southern Part of 

 the Yorkshire Coal-field, and the Probable Manner in which these 

 and similar Changes have been produced. Froc. Geol. Soc. W. 

 Eidimj Yorksh. n. s. part ii. pp. 68-77, pi. iv. ; and Trans. N. Eiujl. 

 Inst. Eng. vol. xxv. p. 13. 



Details of changes in these seams between Sheffield and Wakefield. 



. On the Geology of the Central Portion of the Yorkshire Coal- 

 field lying between Pontefract and Bolton- on-Dearne. Proc. Geol. 

 Soc. W. liklincj Yorlsh. n. s. part ii. pp. 108-112, pi. vi. (map). 

 Stratigraphical details as indicated by two leading sandstone beds, 

 the Pontefract or Houghton Common Eock and the Prierley or Ack- 

 worth Eock. W. H. D. 



. J^otcs on the Yorkshire Coal Field. Journ. Iron Steel Inst. 



pp. 305-317 (with discussion). 



Notices the seams in the following order : — Ganister, with analysis 

 bj^ J. W. Westmoreland ; Elland Flag Eock ; Low Moor Measures 

 (general section); Black Bed Coal; Ironstone Measures (in a band of 

 carbonaceous shale), with section showing thicknesses ; Beeston Bed 

 Coal; Middlcton Main (section); Haigh Moor Coal; Swallow Wood 

 Coal ; Silkstone ; Barnsley, with analyses from " Third Eeport on Coal 

 suited to the Steam Navy;' Blocking Ccal ; Barcelona Coal; Gaw- 

 thorpe Coal; Warren House Coal. Thinks that this coal-field, hitherto 

 so little worked, will in the future give large supplies. R. B. N. 



. The Age of the Eoeks of Charnwood Forest. Nature, vol. xv. 



p. 97. 



Comments on the likeness of the sheet of crystalline rock and beds of 

 highly altered conglomerate and breccia of Charnwood to the lava-flows 

 &c. of the Lake District. States that sections show that the bosses of 

 dioritic rock near Markfield were older than the slates surrounding 

 them, and suggests the possibility of the bosses being the projecting 

 points of an underlying nucleus of Laurentian rocks, which need not bo 

 composed of gneiss, as are those of the Hebrides. C. E. D. 



Grimshaw, W. J. On the Method of AVorking " Bearing Mines" at 



Leycett, Staflbrdshire. Trans. Mancli. Geol. Soc. vol. xiv. part vii. 



pp. 155-108. 



Leycett Collieries are 4 miles W. of Newcastle-under-Lyne, and W. 



of the great Staffordshire Fault and of the Apcdulo Hall '•saddle.*' 



E. of this the dip is small ; W. of it very variable and often steep. 



When the ccal dips 30° or more it is a " rearing mine." C. E. D. 



