File:The Quarterly journal of the Geological Society of London (12645499354).jpg

184
PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .DeC. 13,
E. by S.
stone and marble, of grey, yellowish, and occasionally pink colours,
which at Untersberg near Salzburg, around the valley of Gosau, and
at numerous other places, plunges under strata of impure limestone,
marl and sandstone, charged with fossils of the gault and chalk. In
the western parts of Savoy, however, it is more clearly divisible into
three zones than at the city of Neufchatel itself, and the diagram of
the Montague du Chat already given, explains the fact (see fig. 3).
In another section west of Chambery, which I made in company
with the Canon Chamousset, the order of the strata is exhibited in
this diagram (fig. 5). The lowest rocks visible are the Oxfordian
T.. - W. by N.
Fig. 5.
Tertiary. . ^
r b.
Cretaceous. •. a*
i a.
1 &2.
Marine molasse.
Freshwater limestone and conglomerate.
Upper Neocomian (Chama ammonia),
Bliddle Neocomian (Spatangus retusus).
JiOwer Neocomian .Oyster bands).
Oxfordian Jura and coral rag limestone.
limestones and shale, and the coralline limestone before adverted to
(Nos. 1 and 2) which constitute the uppermost Jurassic band of this
region. On this reposes the lowest neocomian («), which is a hard
siliceous limestone with small, sharp-plaited Ostrese, a small Terebra-
tula, Nerinaea, &c. The middle neocomian (a*) consists of alterna-
tions of bluish grey marly limestone and bands of green-grained calc
grit and beds of chert, and in this band most of the fossils occur, in-
cluding the very characteristic form Spatangus retusus. The upper
division .b) is a whitish limestone, often in a state of marble, which
in Savoy contains both Hippurites and the Chama .Caprotina) am-
monia (D'Orb.).
For the most part, however, in its prolongation along the flanks of
the Savoy, and particularly in the Swiss Alps, the neocomian is divi-
sible into two great subformations only ; the lower being dark-
coloured and marked by the Gryphcea Couloni (Leym.), Rhynconella
(Terebratida) depressa (D'Orb.), and Spatangus retusus (Lamk.)
(Spatangus-kalk, Studer), and the upper being a light-coloured hme-
stone containing the Caprotina ammonia (the Schratten-kalk of
Escher), is a sure and excellent horizon throughout the greater part
of the Alpsf.
Cretaceous Greensand or Gault of the Alps. .Turriliten-Etagef
Escher.) — The largely exposed neocomian limestone of the Savoy Alps
supports, as above stated, in various escarpments, a thin zone of
dark-coloured marly limestone, occasionally freckled with grains of
chlorite, and abounding in fossils. In a collection made by my
guide, Auguste Balmat of Chamonix, at the Montague des Fis, Pro-
fessor Pictet of Geneva recognized Ammonites cristatus (De Luc) ; A,
Hugardianus (D'Orb.) ; A.Mayorianus (D'Orb.) ; A. injlatus (Sow.) ;
t It is worthy of note, that this upper band, as distinguished by the Caprotina