136 M. Charbaut on the 



Geographical disposition of the Rocks of the Gri/phite 

 Limestone formation. 



It has been seen from vhat precedes, that the country, 

 about which I am occupied, does not shew at any point 

 the first beds of this formation ; the rock on which they rest, 

 is buried at too great a depth for observation. 



The rocks of the gryphite limestone generally form, at the 

 foot of the first platform of the Jura, the bottom of all the 

 valleys, the greater part of the hills of little elevation, that 

 are rounded and cultivated to their summits, and the base of 

 all the slopes and hills. When they are not covered by the 

 rocks of another formation, they are almost always found 

 masked by alluvium, filling the bottom of the valleys, and 

 by vegetable soil. It follows that their study oflfers many 

 more difficulties than that of the superior rocks, the numerous 

 escarpments of which readily expose to the observer the dis- 

 position and composition of the beds. 



It is only by assembling numerous partial observations 

 that we can be enabled to describe them completely. I 

 shall not here undertake to trace all those which have led me 

 to the results I have made known ; but I propose to notice 

 the principal, and the localities that alford the most curious 

 geological facts. 



In this respect, the basin in which the town of Lons le 

 Saunier is situated, ought first to engage our attention. To 

 the south of the town, and at a gun shot from Montaigu, on 

 the neck of land separating the basin of Lons le Saunier 

 from that of Macornais, beds of gryphite limestone are seen 

 with the direction of N.N.W and S.S.E. (onze heures de la 

 boussole), and an inclination of 59° to the east; descending 

 to Lons le Saunier, and following their direction, these beds 

 first disappear under the vines, they afterwards shew them- 

 selves on the road above, with a thickness of from 25 to 30 

 centimetres [10 in. to 1 ft.] of limestone without gryphites, 

 with arenaceous veins ; an outcrop of partition limestone 

 (calcaire cloisonne), is seen at eighty paces towards the 



