124 Scientific Intelligence. 
as Favre supposes, the whole succession of formations from the o 
the carboniterous inclusive, so involved by foldings and inversions 
has hitherto been impossible to determine their real structure. 
But even if we admit with Favre the paleozoic- age of the pro 
formation described by Gras and Rozet, we cannot agree with 
limiting to the rocks of that period the action of the metamorphic 
s. The development of a talcose character in the jurassic sha 
cannot regard as the result of a mechanical process, and we 
evidences in the Alps of the metamorphism of still higher rocks. 
As early as the year 1834 Keferstein had asserted that the granites 
Mont Blanc are nothing more than altered strata of flysch, (Matwge 
schichte des Hrdkirpers, i, 286-292; Bul. Geol. Soc. de France, {1}, 
So 
2 
one which we propose to consider at an ear! 
In conclusion. we hasten to say, that although 
the views of Mr. Favre, we are not less grateful for his 
2. The Geological Structure of the * Jornada del Muerto,” New 
being an abstract from the Geological Report of the Hxpedition um 
John Pope, U.S. Top. Hng., for boring Artesian Wells along the. 
the 32d parallel ; by G. G. Suumarp, M.D., Geologist of the Expé 
(Trans. Acad. Sci, St. Louis, vol. i, No. 3, p. 841, 1859)— 
gives a description of the geological structure of a district 
lying immediately east of the Rio Grande, and between the 32d 
parallels. The “Jornada del Muerto” is described as a gentl 
plane, of an elliptic form, from twelve to forty miles in breadth, # 
tending from near the southern extremity of the Donia Ana 
eighty or ninety miles in a N.N.W. direction. It is bounded 
and west by ranges of mountains, varying in their elevation 
three h d 
mainly 
s and sandsto 
form a belt of low hills along the eastern side of the 
We 
