630 The American Naturalist. [July. 
Society respecting the action of soft strata that have either naturally or 
artificially been deprived of their original support, some observations 
that seem to have an important bearing. The great open quarry of 
the Rio Tinto mines (near Huelva, Spain) is 400 m. long, 200 m. 
wide, and nearly 100 m. deep. On the southern side there is a mass 
of clayey schists deprived of support, and having normally a dip to 
the north. These schists are now taking on, at least near their surface, 
a dip to the south, and this dip extends at least five metres deep. At 
the bottom is a mass of solid ore, against which the lower beds of the 
schists are reduced to powder which is easily washed 'away by rains, 
and is expelled by the pressure of the upper layers. This removal 
causes the settling and gradual overthrow of the upper beds. Not 
many kilometres distant a similar phenomenon occurs, but here the 
agent is a torrent which has gradually scooped out a ravine. That 
which at Rio Tinto has taken place so rapidly that its progress can be 
noted from month to month, may easily have occurred more slowly in 
numerous places where the removal of material has been slow ; and M. 
Menteath asks whether it has not often been the case that geologists 
have estimated the dip of the strata from this comparatively recent, 
yet in many cases extensive, reversing of the normal dip. 
M. W. Kilian recently presented before the French Geological So- 
ciety a geological description of the Montague de Lure in the depart- 
ment of Basses Alpes. This work of 458 pages and 11 plates treats of 
the physical constitution of this mass ; of its strata, which commence 
with the Trias and end with the Tertiary ; of the dislocations which 
have given the chain its present relief; and of its palaeontology, with 
a description of some interesting species found in it. 
The new map of the geology of the environs of Paris, on a scale of 
1-20,000, is the most complete yet made. The gypsose period is sub- 
divided, and the Pleistocene deposits are carefully shown. Soundings 
taken in the jjed of the Seine have proved that under the river exists a 
stratiun of gravel 10 to 15 metres thick. The highest gravels of the 
terraces are at I.agny, 19 metres above the Marne, and at Poissy, 27 
metres aljove the Sf inc. 'i"he surface of the chalk is not as much cut 
uj) by ravines as was supj)osed, but has uniform slopes consisting of two 
Carboniferous.— The Bulletin of the French Geological Society 
Nov., 1888, to Jan., 1889) has a note by H. E. Sauvage upon the 
'aleeoniscidae of the Commentry coal-beds. These beds belong to 
lie ui)per part of the coal measures. Some 400 specimens of fishes, 
