388 THE CONE OF THE TINIERE. 



We must not, indeed, place too much reliance on them as yet, 

 but if many calculations made on different data shall agree 

 in the main, we may at length come to some approximate 

 conclusion. 



The first of these calculations we owe to M. Morlot. The 

 torrent of the Tiniere, at the point where it falls into the 

 Lake of Geneva, near Villeneuve, has gradually built up a cone 

 of gravel and alluvium. In the formation of the railway this 

 cone has been bisected for a length of one thousand feet, and 

 to a depth, in the central part, of about thirty-two feet six 

 inches above the level of the railway. The section of the 

 cone thus obtained shows a very regular structure, which 

 proves that its formation was gradual. It is composed of the 

 same materials (sand, gravel, and large blocks) as those which 

 are even now brought down by the stream. The amount of 

 detritus does, indeed, differ considerably from year to year, 

 but in the long-run the differences compensate for one another, 

 so that, when considering long periods, and the structure of 

 the whole mass, the influences of the temporary variations, 

 which arise from meteorological causes, altogether disappear, 

 and need not, therefore, be taken into account. Documents 

 preserved in the archives of Villeneuve show that in the 

 year 1710 the stream was dammed up, and its course a little 

 altered, which makes the present cone slightly irregular. 

 That the change was not of any great antiquity is also shown 

 by the fact that on the side where the cone was protected by 

 the dykes, the vegetable soil, where it has been affected by 

 cultivation, does not exceed two or three inches in thickness. 

 On the side thus protected by the dykes the railway cutting 

 has exposed three layers of vegetable soil, each of which must, 

 at one time, have formed the surface of the cone. They are 

 regularly intercalated among the gravel, and parallel to one 

 another, as well as to the present surface of the cone, which 

 itself follows a very regular curve. The first of these ancient 



