204 Abstract of Foreign Memoirs. 
exported to Liverpool. It is not improbable that the Mountain-. 
limestone range along the North-Welsh coast would display more of 
the ‘pockets’ similar to those at Nant-y-Gamer; and geological 
tourists, who may be passing through the district, would do well to 
examine it with the hope of detecting some organic remains, as 
until this evidence is afforded the true geological age of the deposit 
must be somewhat uncertain. 
The curious hollows and cavernous openings resulting from the 
singular irregularity with which it disintegrates has preeminently 
rendered the Mountain-limestone a preserver of little remnants of 
later formations: most of the bone-caverns, with Pleistocene 
remains,—the little Tertiary outliers of Tipperary,—the rich Rheetic 
remains discovered by Mr. C. Moore near Frome, as well as the 
Nant-y-Gamer deposits, all owe their preservation to the existence 
of cavities of various forms and character in the Mountain-limestone, 
without which they must have succumbed to the process of denuda- 
tion. 
ABSTRACT OF FOREIGN MUEMOTRS.- 
—— $— { 
ON THE OCCURRENCE OF FRESHWATER SHELLS IN THE PERMIAN 
Rocks oF THURINGIA. 
By C. W. Gimpet, with Remarks by H. B. Grinirz. [Neues Jahrbuch, 1864, 
p. 646, &e.] 
N the south-western margin of the Tbiiringer-Wald and the 
Fichtelgebirge occurs a zone of Rothliegende, here and 
there interrupted, with certain small coal-fields, as those of Erben- 
dorf and Stockheim, in which Plants of Upper Carboniferous age 
have been found; and at Irmelsberg, near Crock, is a similar 
deposit, where a workable bed of coal also occurs. Last summer 
the author visited the last-named place, where a new shaft was 
being sunk, and was astonished to find a coal-bed which, by its posi- 
tion and the character of its fossil Plants, evidently belonged to the 
Rothliegende, the lowest member of the ‘Permian’ of Murchison, 
and of the ‘ Dyas’ of Geinitz. 
The Plants, some of which occurred in the roof and others in the 
floor of the coal-seam, were determined by Dr. Geinitz to be charac- 
teristic fossils of the Rothliegende; but a greater importance was 
attached to the deposit on the discovery, by Dr. Giimbel, of Fresh- 
water Shells in the same overlying shale in which some of the 
Plants were found. 
The lower plant-bearing stratum,—a fine-grained sandstone, over- 
lying beds known to belong to the Rothliegende,—contains Walehia 
piniformis, Schl.; Cyatheites confertus, Sternb., sp.; C. Candolleanus, 
Brongn., and Calamites gigas, Brongn.: then follows the coal-bed 
itself, which has a thickness, at the outcrop, of from 14ft. to 4ft., 
and is overlain by a black shale, 1 foot thick; next comes the 
upper plant-bearing stratum, which is a fossiliferous coal-shale, and 
contains, in an intercalated layer, Freshwater Shells and an Estheria, 
