OUTLIERS AND INLIERS. 67 



In this section (fig. 20) a few hills to the north of London are shown, 

 capped with Bagshot Sand, which alone exist as evidence of a con- 

 tinuous stratum, which has been denuded from the surrounding country. 



HIGHBEACH HAVERINQATE 



Fig. 20. 



Over the chalk of Hertfordshire are scattered numerous outliers of the 

 Woolwich and Reading beds of the London basin, giving some idea 

 of the former great extension of that deposit. 



Outliers are frequently widely separated from the principal mass 

 with which they are connected. Thus an outlier of the Lias in 

 Cheshire finds the nearest mass with which it could have been con- 



MASS OF THE 

 FOR MAT in fj 

 1 



Fig. 21. Section of Outlier. 



MAP. 

 Fig. 22 Map of Outlier. 



tinuous in Leicestershire ; and other Lias outliers in Belfast, and the 

 valley of the Eden, have the regular formation nearest to them at 

 Whitby. An outlier is always newer than the formation around it. 



An irilier is an older 1 deposit which is exposed by the removal of 

 a portion of an overlying stratum, so that it lies within a girdle of 

 the surface rock. The most considerable inliers in this Country are 



CHALK (A). 



Fig. 23. Map of an inlier. 



UPPER GREEN SANt) (B). 



Fig. 24 Section of Inlier. 



the Carboniferous Limestone of Derbyshire, which lies within the Mill- 

 stone Grit ; and the Wealden beds of Kent and Sussex, which are sur- 

 rounded by the Cretaceous strata. At Woolhope there is a Silurian 

 inlier rising through the Old Red Sandstone, and at the Wren's Nest 

 near Dudley, another Silurian inlier rising through the Coal. Some of 

 the simplest are seen at Inkpen and Kiiigsclere, where the Chalk is 

 cut through to expose the Upper Greensand beneath. 



Stratification a General Principle. Considerable labour remains 



