Si* Elie de Beaumont's Researches on some of 



discovered in the three groups, which he distinguishes in the 

 beds above the chalk, and the catalogue of species now ex- 

 isting. It is sufficient, that in the series of superimposed beds 

 there are points more remarkable than, others, on account of 

 the changes they exhibit, both in the deposits and in the in- 

 habitants of the same country, to be struck with the accordance 

 of the two orders of considerations above noticed. 



Among those observations which render it impossible to 

 consider the dislocation of beds which characterizes a moun- 

 tainous country as the result of local phaenomena, which may 

 have been repeated in an irregular and successive manner, 

 we may place in the first rank the constancy of the direction 

 in which sedimentary beds are tilted up even for immense 

 distances. 



Practice has taught miners from time immemorial the prin- 

 ciple of constancy in directions, and it is one of those circum- 

 stances which they most usefully employ in their researches. 

 The observation of constancy in the direction of beds in the 

 coal-measures, has served to discover a bed of coal at a di- 

 stance, though invisible on the surface. It was by combining 

 the observations made in numerous metallic mines, that Wer- 

 ner ax'rived at the conclusion, that, in the same district, all 

 the veins of the same nature were due to cracks parallel to 

 each other, formed at the same time, and subsequently filled 

 at the same period. The remarkable phaenomenon of con- 

 stancy of direction has been gradually shown to be more im- 

 portant, by the labours of those geologists who since De 

 Saussure and Pallas have attentively examined mountain 

 chains. It has been admitted by degrees, that the circum- 

 stance which best characterizes mountain-chains, when com- 

 pared with each other, is the direction which the elevation 

 of the beds has impressed upon them, — a direction naturally 

 observable in the crests composed of such beds. For more 

 than thirty years M. Humboldt has pointed out the equally 

 remarkable accordances and discrepancies observable in the 

 direction of mountain-chains, whether close to, or remote from, 

 each other. M. von Buch has also shown that the mountains 

 of Germany are divisible into at least four systems, clearly 

 distinguishable from each other by their directions. So clear 

 a mode of distinction even led him to conceive that the various 

 mountain systems were produced by phaenomena independent 

 of each other ; and it is at the same time very probable, that 

 not only, as is proved by observation, all beds upheaved at the 

 same time have been so raised in the same direction, but also 

 that this constancy in the direction of the upraised beds in a 

 certain assemblage of mountains, is the result of this collection 



of 



