1848.. MURCHISON ON THE STRUCTURE OF THE ALPS. 209
Returning to the chief section (fig. 17), I specially call attention to
the ascending succession, as seen to the south-east of Burgberg, above
the intermediate gryphite zone (e). As on the east flank of the
Grimten (fig. 18), so here we see schist and thin bands of dark flyscli
with white veins, intercalated between the greensand and impure lime-
stone with the Gryphsea and the lower zone of nummulites. The
mineralogical transition is here equally perfect, nummulites are also
abundant, together with Pectens, Spondyli, and other fossils of
the zone, the beds being also ferriferous, but offering some local
peculiarities, such as small cavities in the green sandy calciferous
grits. This band (/) is overlaid by glossy light grey and dark
schists, that have been worn into a small depression, which is fol-
lowed by a second ridge of nummulitic rock. The mass of this is a
greenish, yellowish sandstone, or sandy calc grit, which graduates
into a hard siliceous limestone containing large Echini, Pectens,
Terebratulae, as well as Nummulites, and is very peculiar from the
small flakes of chlorite which occupy the structural divisions of some
of the foraminifera. Shale and thin stone bands recur in another
slight depression, followed by another course of nummulitic limestone
of grey colour, but also containing iron, whereon an ancient castle
stands ; then another depression in shale, &c. ; and lastly a great band
of nummulitic limestone of about 150 feet in thickness, which, being
thin-bedded, sandy, and subconcretionary in its lower parts, passes
up into very thick beds of hard grey limestone charged with Num-
mulina millecaput, Orbitolites, &;c. This limestone, when followed
to the Starzlach, plunges under other courses of schist and sandy
shale, forming part of the great overlying masses that occupy both
banks of the river Iller, between Sonthofen and Ober Maiselstein,
but which are denuded in the plain of Sonthofen.
I may complete this ascending section of the formations in the
valley of the Iller by stating, that although a consecutive ascending
order is observable in the hills to the east, the same order cannot be
followed without breaks, curvatures and reversals in the chief de-
pression or on its western side. It is manifest, however, that all the
sandstones, schists and bastard limestones, which constitute the flysch
on both sides of the valley between Sonthofen on the north and the
Schwarzenberg, are parts of that great group the lower portion of
which inosculates with the nummulitic limestones. (See fig. 19.)
Fig. 19.
Left hank of the Iller , above Sonthofen.
N.N.W. Bolghen. Schwarzenberg. S.S.E.
Valley of
Oberstdorf.

• The small Nmnmulina placentula (Desh.), N. intermedia (D'Arch.), in this