244 SECONDARY LIMESTONES. 



magnesian limestones, it is one of those pernicious 

 ones which has produced considerable confusion; 

 serving further, like others, in lieu of a description, 

 while also appearing lo involve knowledge unknown 

 to others, and thus carrying the semblance of profun- 

 dity. Thus also it has been used to distinguish those 

 limestones, in whatever situation, which have under- 

 gone the influence of granite or trap ; as if a mere 

 term could be a substitute for a knowledge of the 

 circumstances attending any rock. The science would 

 make no small gain by rescinding this, and some 

 others, from its catalogue of words. 



The last limestone, as it is the uppermost of the 

 secondary strata, is the Chalk ; proceeding upwards, 

 when complete, from the beds called chloritic chalk 

 to chalk marl, and subsequently to hard and to soft 

 chalk. In England, this deposit is very conspicuous, 

 from its extent and purity ; but, though far less con- 

 siderable than the oolithe, it occurs also, if often with 

 characters less marked, in various parts of Europe : 

 as in Scania, Jutland, and Zealand, in France, extend- 

 ing through the Netherlands, in Poland, following 

 the course of the Carpathians, in Bohemia, Galicia, 

 and Silesia, in Italy, in Spain, and in the Ionian islands. 



The collective beds are often of great depth, as in 

 our own country ; and the upper ones are noted for 

 containing strata of flints, while the inferior are free 

 from them, giving rise to corresponding distinctions. 

 The accumulations of similar flints in particular places, 

 seem to indicate the waste of an analogous including 

 rock ; denoting its former presence in places where it 

 no longer exists, as in Scotland, in Guernsey, and in 

 many parts of the continent. Beds of clay and of marl 

 also occur in this deposit; the green earth which cha- 

 racterizes the chloritic chalk, being found chiefly in the 



