og% UNUSUAL ARRANGEMENT OP STRATA. 



The strata What appears to me worthy of attention is the solid cu- 



they might neifbrm summit, that unites two inclining sides, which are 

 have been ex- near 100 met. [100 yards] high from the river, and we know 

 thinnesL° not now c ^ ee P tne - v descend. 1 ne particles that compose 

 this summit are as intimately united as those of the rest of 

 the stratum : there is no perceptible joint, no regular fis- 

 sure, indicating the strain experienced by these strata in 

 bending, if they were originally deposited in a horizontal 

 situation: and supposing the calcareous matter to have been 

 sufficiently soft when this happened, to bend without crack- 

 ing, I cannot conceive what cause could produce a nearly 

 pointed summit, resembling rafters united by a sloping cut, 

 the obvious effect of which is an increase of thickness, 

 while a simple bend necessarily diminishes it. Can the dif- 

 ferent velocities of the masses, combined with the pressure 

 of the adjacent parts, which so happily account for strata 

 bent on a small scale, apply equally to an entire hill, bent 

 in the great, if the expression may be allowed, and the 

 summit of which is not overtopped by other mountains*? 

 Geology of the These observations lead me to say a few words on the 

 country. """^ geological constitution of that portion of the departments 

 of the Sambre and Meuse and of the Ourthe, which is in- 

 cluded between the Meuse, the Lesse, and the Ourthe. 

 The strata, that form the soil of this country, exhibit every 

 possible variety of inclination. They not only vary from 

 horizontal to perpendicular, but we every instant meet with 

 curvatures or folds. Every thing indicates prompt and 

 violent catastrophes. The direction f of these strata too 



prolongation, like those they cover ; or that they would diverge, and 

 the angular bend that unites thein disappear at some distance from the 

 precipice: for we can scarcely suppose, that the surface terminating 

 all these strata at the top of the hill is exactly parallel to the line of 

 junction of the central strata, and that it retains this parallelism 

 throughout their whole extent. Note of the French editors. 



* For some other siugular arrangements of strata, see Journal, vol. 

 XX, pages 62 and 64, and Plate II. 



f I make a distinction between the direction and inclination of the 

 strata: the latter is indicated by the angle, which the horizon for m» 

 with the luwei- plane of the stratum, while the direction is the com- 

 mon section of this plane with that of the horizon. 



presents 



