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presence of Product! and Encrinites in Crystalline rocks of the East- 

 ern Alps ; and hence it is probable that some of these masses, in 

 which no organic remains have yet been discovered in the Western 

 Alps, may occupy the place of palaeozoic deposits. Again, a third 

 group is, by its mineral aspect, also apt to be confounded with the 

 primary rocks ; and yet, as has long been known, the Lias and Ju- 

 rassic strata are included in it. 



Since the day when M. Elie de Beaumont first exhibited to the 

 astonished geologists, Belemnites in chloritic and micaceous schist ! 

 these highly altered Lias rocks have excited the most lively interest ; 

 more particularly as the Belemnites were found associated with 

 plants which M. Adolphe Brongniart identified with species well 

 known in the Carboniferous deposits. Anxious to explain this ap- 

 parent anomaly, M. Sismonda, who, on a former occasion as well as 

 on a recent one, was the companion of M. de Beaumont, following 

 these masses from Mont Blanc to the department of the Lower 

 Alps, where they are most charged with fossils, has arrived at the 

 conclusion, that whether crystalline limestones, quartz rocks or 

 quartzose conglomerates, all these rocks belong to the great Ju- 

 rassic series, from the Lias to the Portland stone inclusive ; the re- 

 spective formations being more or less metamorphic as they ap- 

 proach to, or recede from great centres of pi u tonic eruption. 



On the curious and long-disputed point of the relations of the 

 beds with Belemnites to those with coal plants, M. Sismonda, 

 sustaining the views of M. de Beaumont, asserts that the sections 

 fairly exhibit alternations, and that the difficulty cannot be set aside 

 by supposing one of those reversals en masse, so common in mountain 

 tracts, and by vvhich older strata are often superposed on younger. 

 M. Sismonda agrees, therefore, with M. de Beaumont in believing 

 that the plants in question lived near the spots in which they are 

 now found, and during the same period as the Belemnites of the Lias. 

 It remains for naturalists to explain how certain plants, whose forms 

 indicate a climate of high temperature, may have continued to grow 

 during successive periods in favoured spots, though their congeners 

 had long been destroyed in other parts of the world. 



Proceeding upwards from the Lias as a base, and seizing here 

 and there upon remnants of the strata from which the impress of their 

 origin has not been obliterated, M. Sismonda refers certain lime- 

 stones, grits and schists to the Great Oolite. Another group, com- 

 posed of grits, quartzose conglomerates, psammites and schists, in 

 some parts metamorphic and unconformable to the preceding, (and 

 which, extending over the Genevese and Piedmontese Alps, is also 

 largely exhibited in the Alps, in the Col di Tenda, and in the Tanaro) 

 is referred by our author to the age of the Oxford clay ; though 

 preceding geologists, misled by the red colour and other characters, 

 had referred it to the New Red Sandstone. Among the uppermost 

 deposits of the oolitic series of the Alps, M. Sismonda recognizes 

 in certain limestones highly charged with zoophytes, the representa- 

 tives of the Upper or coralline Oolites and Portland rock of England. 

 In the Apennines of Liguria he has observed the Jurassic formations 



