Chap. XVII.] CAKBONIFEKOUS KOCKS IN THE ALPS. 
423 
boniferous shells occur in the Austrian or Eastern Alps. With these data before 
us, and looking to the prodigious amount of metamorphism, dislocation, convolu- 
tion, and inversion to which the component parts of that chain have been sub- 
jected in their extension to the west, we can have little difficulty in imagining 
how the Silurian and Devonian strata have there passed into a crystalline state j 
while the sole remnants of the Carboniferous rocks, identifiable through their 
organic remains, are the plant-bearing conglomerates and schists of the Valorsine 
and of certain tracts around Mont Blanc, which have been so twisted up as often 
to appear to be intercalated among the Secondary rocks. Indeed the long-dis- 
puted question of the age of the anthracites of the Tarentaise has been at last 
settled by the labours of MM. Vallet, Lory, Pilhet, and A. Favre ; and, since 
the Meeting of the French Geologists held in 1861 at St. Jean de Maurienne, it 
has been admitted by most geologists that these schists belong to the true Car- 
boniferous era. 
Note. — The ensiform bodies occurring in the Trilobite-slates of St. Leonhard, La Sarthe, 
France, and supposed by M. Marie Eouault to be Ichthyolites, have not the least relation 
to Vertebrata, or possibly to anything of higher order than Fucoids. See Appendix Ot 
of the last edition of this work, and Comptes Eendus de l'Acad. vol. xlvii. p. 469. In 
fact, no trace of Vertebrata has been discovered in the Silurian rocks of France. — 
April 1867. 
