198 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DcC. 13, 



valves, and occasionally the large Conoclypvs conoideus and other 

 Echinoderms that characterise the deposits of Sonthofen, Kressenberg, 

 and other places in Bavaria and Austria. 



All the dips of the rock-masses in this tract are inverted ; for the 

 molasse and nagelflue of Einsiedeln being the eastern prolongation of 

 the Rigi and Rossberg equally plunge S.S.E., and seem absolutely 

 to be overlaid by its older neighbour the nummulite limestone and 

 "flysch ;" the latter formation being in its turn so thrown over that 

 its younger member lies against or dips under the secondary rocks. 

 In this manner the oldest portion of the nummulitic group is in con- 

 tact with the tertiary conglomerates (fig. 13), which I shall hereafter 

 prove are the upper part of a great series containing some marine 

 shells of existing species ! 



Nummulitic Rocks and Fish Slates of Glarus. — Nummulitic lime- 

 stones reappear in broken troughs at various other points throughout 

 the little canton of Schwyz ; but in following them into the canton 

 Glarus, the associated strata, or rather the beds immediately over- 

 lying the zone characterized by nummulites, presents a striking zoo- 

 logical feature. The bands of flysch above the nummulites, indeed, 

 as in many other places, contain fishes' scales and teeth, particularly 

 certain dark schists and marls of Savoy and various parts of Switzer- 

 land. In Glarus, however, and notably near Engi in the valley of the 

 Sernft, where these black beds have undergone much induration, 

 they are largely quarried under the name of Glarus slates, and 

 are well known to collectors for the numerous fossil fishes they 

 contain. On visiting the quarries I found them totally void of any 

 slaty cleavage ; the so-called slates being true calcareous flagstones 

 with a few diagonal veins of white calc spar. They dip away 30^ 

 and 40° E.S.E. from the face of the ridge of the most ancient rock 

 of this tract, usually called the Sernft conglomerate. At the spot on 

 the west side of the valley, where the fish beds are quarried, there 

 is no \dsible relation to any nummulitic rock ; but the same calcareous 

 flagstones with white veins, and which are clearly one of the nume- 

 rous varieties of "flysch," can be followed up the valley of the Sernft 

 to heights of 1 000 feet and more above the water-course ; and to the 

 east of Elm they are associated with and overlie strong bands of 

 nummulitic limestone. This position was clearly seen by M. Escher 

 and myself as we ascended from Elm to the high pass of Martin' s- 

 loch. In treating of some of the contortions, inversions, and breaks of 

 the Alps, I shall have occasion hereafter to return to the considera- 

 tion of this very remarkable tract ; but whether the strata be there 

 overthrown " en masse " or not, has nothing to do with the present 

 question ; for the calcareous flagstones identical with the fish beds 

 quarried as Glarus slates, and which are in truth a direct prolonga- 

 tion of them, are fairly dovetailed between two courses of nummulite 

 limestone, in the lowest of which I perceived the large Nummulites 

 millecaput, and in the other a greenish-grained deep-coloured sili- 

 ceous limestone with another and smaller nummulite, both of which 

 occur in numerous places in association with all the other fossils of 

 the group and regularly overlying the cretaceous rocks. 



