gQ3 CEOLOOICAL OBSERVATIONS IN^ FRANCE. 



zontal strata. On the E. N. E., toward the valley of Boraes, 

 or the Alps, which lie beyond it, the strata decline with a 

 gentle and almost uniform slope. On this side we find strata 

 of soft sandstone imposed on calcareous strata inclining un- 

 der an an^le of 45°. Similar strata are found on the little 

 Saleve, sloping- in tlie same manner to the east. The sand- 

 stone^strata extend to some distance from the foot of Saleve, 

 joining underground those of the hill of Essery, and still 

 fetaining the same direction. The brook Viezou has hol- 

 lowed itself out a very deep hed in this soft standstone. The 

 Arve too has made its way across it : and in the little Sa- 

 leve we see beneath it strata of calcareous breccia, cover- 

 ing those of compact limestone tiiat form the body of the 

 mountain. The sides of the mountain toward the village of 

 Croisette are woodj^, and on the top the vegetable mould 

 Covers a considerable bed of white sand. In the interior of 

 the calcareous strata are petrified marine bodies in great va- 

 riety, some indications of coal, several nuclei of silex or pe- 

 trosilex of a naturally round form, iron in the state of earthy 

 oxide, &c. 

 ^Voifoas. Mount Vuirons, three miles farther from the Leraan lake 



than Saleve, would be in some measure parallel with it, if 

 it did not incline more to the south. Its summit forms a 

 long ridge. Ou the side next the lake its slope is gentle for 

 about two thirds of its height, where there is a small plain ; 

 and thence it becomes very steep, and is covered with firs* 

 it is comyjosed "chiefly of a calcareous gritstone, the nature 

 of which however varies greatly ; for the southern part of 

 its ridge is a kind of primitive puddingstoae, in which I 

 have found nuclei of a fine granite with red feldtspar and 

 black mica, the most rare, as Mr. Deluc observes, in that 

 part of the Alps which" approaches Geneva. Its declivity 

 - toward the Alps is much more steep than that of Saleve. 

 Near the southern extremity, about half way up the moun- 

 tain, is a large limestone quarry, the strata of which are 

 • nearly perpendicular to the horizon, lie east and west, and 

 include several species of marine petrifactions. Among 

 others Mr. Deluc found two large bufoniteS, which he co'n- 

 iniders »s new. 



The 



