, f 
Geology and Mineralogy. 477 
are derived from the precipitation of iron oxide from its soluble 
salts in waters receiving the drainage of a region, the waters 
times strata e- 
Stone or of ‘late, en made by quiet methods of deposition, 
jasper, another ro ae’ of fine and quiet sedimentation; and the 
existence of beds of aluminous magnetites, which contain almost 
no silica. Dr. Julien states rightly that some magnetite is asso- 
o much overlooked. But Dr. New wherry’s position appears to 
a the right one—that on method is not the usual one, an 
sot Pins thin seams o 
The scnditions ne 8 such as woul ate sea-bottom i Saposii of 
the ore ;- and it is sjunetionalls ater in aopoee so formed the 
iron-sands are not always: epee He ce ie imatat the sediments, as 
is so commonly the case in sands 
e successive phases of a naar acc tiere open seas have 
alternated with immense salt-water mud-flats or marshes, beco ca 
as to confined areas fitted for chemical iron-ore deposits. uch 
are the conditions which the writer has had in view when speak- 
Ing of the ore as originally a marsh-made deposit ; and _ he 
understands to be the view of Dr. Newberr 
10. Overturn folds in the Glaronnaise Alps —The pe of a 
double overturn fold in the Glaronnaise Alps, first presented by 
~ssrared and against: adopted and illustrated with full details by 
Heim, led to an excursion over the region in 1882 by a party of 
Messieurs Lory, de Grenoble, Rothpletz of Munioh and Vilanova 
of Madrid. The the general ee of Heim’s 
conclusion as to the enormous overturn. as fully con- 
vinced as to the double fold. M. Rothpletz adinitved the exist- 
ence of the southern fold, but objected to that of the northern, 
explaining the position n of the formations in the latter region by 
a fault combined with a sliding of the beds —M. & Favre, Ar- 
chives des Se, Phys. et Nat., II, ix, 180, Feb., 1888. 
