SECONDARY LIMESTONES. 



2,37 



secondary strata, they are producing systems of 

 Geology. 



The secondary limestones of Europe are thought 

 to be divisible into the following principal deposits ; 

 but it is as yet unsafe to extend these to other parts 

 of the globe, while no philosophical Geologist can 

 believe that even all those of Europe are understood. 

 The antient geological travellers have not enabled us 

 to profit by their observations; and when Klaproth, 

 recently, describes primary limestone as occupying 

 great spaces in Caucasus, we may safely conclude that 

 he is in error. 



The lowest of these is the "carboniferous" or "moun- 

 tain" limestone, lying beneath the coal series; and the 

 next is the " magnesian limestone" of our own country, 

 above it, supposed to correspond to the alpine limestone 

 to the first " flcetz limestone," and to the zechstein of the 

 continent. Next comes the muschelkalk, thought to 

 be unknown in England, followed, after an interval of 

 sandstone, &c., by the lias, and then by the extensive 

 oolithe series, supposed to correspond to the Jura 

 limestone and other great deposits of Europe, and in- 

 chiding what is called the Jura dolomite. Lastly comes 

 the chalk, with its associated members. The limestones 

 not considered principal, are found, first in the old red- 

 sandstone, and more extensively in the coal deposit; 

 after which they occur with the red marl and the other 

 arenaceous strata, and further, in innumerable anoma- 

 lous situations through the whole remainder of the 

 series ; sometimes acquiring, in England and elsewhere, 

 local distinctions, which I can here rarely notice. In 

 a similar manner, they form portions of the lacustral 

 and analogous deposits. 



The lowest, or " mountain" limestone, under various 

 names, immediately follows the " old" red sandstone, 



