104 



THE GEOLOGIST. 



d'Encombres, in Savoy. By their researches in the gealogy of this 

 country the author, with his brother and M. Bellardi, confirms the 

 conclusion they arrived at in the year 1848, that the anthraxiferous 

 formation of the Alps belongs to the Liassic age. Perhaps no other 

 stratigraphical group has given rise to so much discussion as the one of 

 which we now speak. The presence of coal and anthracite in the 

 limestone-formations of the Alps long ago attracted particular attention 

 to these strata. What would our English geologists have thought, in 

 1830, had they observed a seam of anthracite or coal imbedded in the 

 white chalk of Dover cliffs ? Would it not have led to a strict 

 examination of the stratigraphical relations of this chalk, and a more 

 minute investigation of its fossils ; more especially if these were broken, 

 cemented together, and difficult to determine, as they are in the Col 

 d'Encombres ? That is precisely what has taken place regarding the 

 Alpine strata; and since the year 1830, or thereabouts, up to the 

 present time, they have been shifted about on geological tables and 

 maps, from the white chalk to the coal-measures, from these to the 

 white chalk again; from the latter they have travelled to the Jurassic 

 formations, to be finally* fixed in the Lias. Studer, Brongniart, 

 Brochant, and D'Omalius, have all striven to solve this problem ; but for 

 the elucidation of the discussed points we are mostly indebted to the 

 admirable labours of M. Elie de Beaumont, who first got a glimpse of 

 the real nature and position of the Lias strata of the Alps. 



The list of fossils from the limestone of the Col d'Encombres shows 

 in all 63 species, of which 35 only can be specifically classified by the 

 examination of fossils already known. Of these 35 belong to the 

 superior, inferior, and middle strata of the Lias, with the exception of 

 four, which are attributed by M. Sismonda to the stratum known as 

 the Inferior Oxfordian bed. A remarkable circumstance, which 

 deserves especial notice is, that from Professor Sismonda's account, the 

 fossils which modern palooontologists look upon as belonging to different 

 strata, are, in the Lias of the Alps, all found in one bed. Thus, at 

 Col d'Encombres, all those belonging to the three Lias beds are found 

 in one single stratum. 



"•^ It is impossible to regard this vexed question as definitely settled, even after 

 these late rcsearche!^ of MM. Sismonda and Bellardi ; for we must not forget that 

 M. Favrc, and other equally talented and experienced Geologists, still consider 

 that distiuct Liassic beds are intermixed, by invei'sions, in some cases, with true 

 Carboniferous beds, in these Alpine Anthraxiferous strata ; although some refer 

 the whole to the Jurassic scries, and others place them all in the Carboniferous. — 



Kl>. OF liEOLOGlST. 



