Reports and Proceedings. 213 
such as a central depression of a mountain-range, converting the 
valleys into basins, with, however, many modifications of extent, 
amount, and direction. Prof. Ramsay regards this hypothesis as 
asking for too great a complication of phenomena, to be favourably 
contrasted with his simple hypothesis, that, as glacier-ice does not 
erode the rocky floor over which it passes, and as it can, under cer- 
tain circumstances, move up slopes, the nature of that erosion will 
be, and was dependent—1. On the angles of the slopes over which 
it passed when these slopes were seriously appreciable-—2. On the 
fact that the glaciers sometimes passed from these slopes into low 
grounds, into which the great old glacier-valieys opened.—3. That 
at the mouths of these great old valleys, and sometimes near their 
mouths, where two or more great glaciers met, the downward pres- 
sure of all the accumulated ice of all the tributary valleys would be 
‘greatest.—4. Because of its inertness in such flat ground, the grind- 
ing power of the ice, urged on from behind, would be greatest, in 
accordance with all known physical laws.—And, 5. That as it pro- 
gressed and melted, the ice must have been thinner, and must have 
exercised less erosive power than where it was thick; whence the 
gradual slope of the bottom of these lakes toward their outflows. 
REPORTS AND PROCHEDIN GS. 
——_4+—__ 
GroLocicaL Sooty or Lonpon.—I. March 22, 1865; W. J. 
Hamilton, Esq., President, in the chair.—l. ‘ Notes on the Caves of 
Gibraltar.’ By Lieut. C. Warren, R.E. Communicated by the Se- 
cretary of State for War through Sir R. I. Murchison, K.C.B., F.R.S., 
¥.G.S.—The principal caves at Gibraltar are St. Michael’s, Martin’s, 
Glen Rocky, Genista, Asylum Tank, Poco Roco, and three under 
the Signal Station, on the eastern face of the Rock. The author 
described the chief features of St. Michael’s Cave, stating that it is 
a portion of a transverse cleft through the Rock, and was probably 
open to view at no very remote historical period; and he briefly noticed 
the cave at Poco Roco, which he considers to be a portion of the 
fissure which extends from Bell Lane, in the town, to the village of 
Catalan Bay, the noise of blasting having been heard on more than 
one occasion through the apparently solid rock. In conelusion, 
Lieut. Warren offered his services in the event of a geological survey 
of Gibraltar being undertaken. 
2. ‘On the asserted Occurrence of Human Bones in the aneient 
Fluviatile Deposits of the Nile and the Ganges, with comparative 
remarks on the Alluvial Formation of the two Valleys.’ By the 
late Hugh Falconer, M.D., F.R.S., F.G.S.—In this eommunication 
the author brought together the few instances on record of the oc- 
currence of fossil mammalian remains in the Valley of the Nile; and 
instituted a comparison between the Alluvial deposits of the Nile 
and those of the upper part of the Valley of the Ganges which had 
come under his own observation. According to certain statements, 
fossil human bones have been met with in both of these subtropical 
x 
