Geological Society. 557 
This circumstance, Mr. Strickland thinks, may be explained by the 
less specific gravity of the fresh water requiring a higher column to 
overcome the obstacles met with in its subterranean course. In order 
to ascertain the direction of the current, Col. Brown has had an exca- 
vation made, by which it appears that the stream does nct pass unddr 
the sea at the opposite side of the promontory. Mr. Strickland, in 
explanation of the constant flowing into the land of these streams, ob- 
jects to the proposition that the subterranean current may be absorbed 
by the incumbent soil and evaporated at the surface, as it occurs in an 
island of small extent : but agrees to the supposition that an earth- 
quake has at some period opened a communication between the sea 
and the region of volcanic fire ; that the water being there converted 
into steam, is afterwards condensed in its upward course, and forms 
those hot-springs which exist in various parts of Greece. 
A paper onthe occurrence of fossil vertebre of fish of the shark fa- 
mily in the Loess of the Rhine, near Basle, by Charles Lyell, Esq., 
F.G.S., was afterwards read. 
Mr. Lyell described in a memoir communicated to the Society in 
May, 1834,* the geographical extent of the Loess or ancient silt of 
the Rhine, as far as he had then examined it. In tracing its southern 
limits during last summer, he found it in considerable force at Basle, 
and still higher on the Rhine at Waldshutt, where it contains the 
usual land and freshwater shells, Beyond this point he did not trace 
the deposit; but from the information he received, he believes that it 
terminates between Waldshutt and Schaffhausen. He here alludes 
only to the loamy portion, which can be identified by its fossils ; for 
the gravel beds with which the loess sometimes alternates in its lower 
part, are probably of much greater extent, and are not easily to be 
separated from any other ancient gravel in which bones or shells have 
not been discovered. 
The loess at Basle crowns the summit, and is found on the sloping 
sides of several low hills which bound the valley of the Rhine; but it 
is best seen one or two miles to the south of the town, in the hills 
called Bruder Holz, where it rests upon nearly horizontal beds of 
molasse. The loess has here an elevation of more than 1100 feet 
above the sea; for it is found in places which are more than 300 feet 
above the Rhine at Basle, according to the measurement of Prof. 
Merian, who has also determined that the Rhine at Basle is about 
760 French feet (809 English) above the level of the sea. 
The principal section examined by Mr. Lyell is near the northern 
extremity of the Bruder Holz below the church of the village of Bin- 
ningen. The loess in this place is of its usual yellowish grey colour, 
and is filled with terrestrial and freshwater shells. The lower beds al- 
ternate with strata of sand and gravel, and in one of the loamy strata 
of this part of the series, he found the vertebra of fish, together with 
the following loess shells: Succinea oblonga, Pupa muscorum, Clau- 
* See Proceedings of the Geological Society, No. 41. Vol. II. p. 83; 
Jameson’s Journal, Vol. 19.; and Lond. and Edinb. Phil. Mag., vol. v., 
p. 223. 
