Notices of Memoirs. 1 
ent; this river flowing into a sea shallow throughout, and regularly 
stirred to its bottom by very violent tidal currents. In the summer 
of 1863, Dr. Lorenz, having ascertained the specific gravity of water 
taken in different depths at fifty points along a line of nine geogra- 
phical miles from Neuhaus to Heligoland, states with confidence 
that there is no brackish stratum spreading over perfect sea-water 
at the mouth of the Elbe: the brackish water, gradually passing into 
completely salt water, extends to the sea-bottom. The water here, 
however, taken as a whole, is divisible into a system of obtuse 
wedges ; so that constantly a wedge of fresh water, with its edge 
turned seaward, is sliding over a wedge of somewhat more saline 
water. The components (length, thickness, and angles of conver- 
gence of the lateral planes) of these wedges, when construed by 
means of average values for any fresh-water current, may serve as 
a basis for an empirical formula, by the aid of which (the transversal 
section and velocity of this current, the depth and shape of the 
marine basins into which it flows, and the nature of the tides in it 
being known), the dimensions of the bulk of brackish waters and 
the distribution of salinity in them, may be approximately deter- 
mined. Besides the physical interest connected with them, such 
determinations are highly interesting, in respect to their influence 
on the distribution of both living and fossil organic beings. 
Count M. 
On THE Liassic CrinompAL LimesTonr oF FREIAND, ImBACH-GRABEN, AND GRos- 
sav, Lower Austria. By Professor Prrers. (Proceed. Imp. Geol. Institut. 
Vienna, March 15, 1864.) 
HE limestones of the first two of these localities, closely allied to 
the Hierlatz-strata of the Eastern Alps, contain Rhynchonella 
furcillata, Theod., Waldheimia Lycetti, Dav., Terebratula subovoides, 
Roem., Rhynchonella Moorei, Dav. (a species of the West-European 
Lias, also found lately in the Banat), Rh. tetrahedra, Sow., Fh. cal- 
cicosta, Quenst.., variously shaped and partly gigantic Spiriferine, 
of the type of Sp. rostrata, Schloth., mixed with species charac- 
teristic of the Hierlatz-strata. The limestone of Grossau, chiefly 
composed of Pentacrinus basaltiformis, lies between Carboniferous 
Gresten-strata and an extensive series of Liassic variegated marls. 
Among the seven species of Brachiopods occurring in it, three cor- 
respond to those of the Hierlatz-strata, and two or three are Extra- 
Alpine forms, far spread in the Middle Lias of Germany and 
North-western Europe. All the three localities are consequently 
intimately connected with the Middle Lias of the Extra-Alpine 
regions; and may point to the conclusion, that the Limestone of 
Hierlatz also is not an absolute equivalent of the Lower Lias. The 
diserepancies between the Alpine and the Extra-Alpine Liassic 
deposits may be explained by the geological perturbations which 
influenced the Southern and North-western German Lias and their 
faunz, as also by immigrations from the Eastern faune under the 
influence of marine currents, dependent on the extent and confor- 
mation of the coast.—Count M. 
WMO —— NOT Vaile C 
