a 
Ps 
 - 
W. J. McGee—Superposition of Glacial Drift. 301 
“a and taking up in alcohol. The 
y ammonium carbonate was dissolved in 
evaporated to dryness and weighed, the lithia found amounted 
to from one-quarter to one per cent. 
The solutions were kept as far as possible from all contact 
with glass, the evaporations being carried on in large platinum 
ishes. The reagents were carefully selected and purified. 
Sodium hydroxide free from aluminium and silica was obtained, 
prepared from metallic sodium. Owing to the limited amount 
of material from Penig only three-quarters of a gram was used 
in the determinations, and duplicates of the water and fluorine 
determination were not obtained. For the occurrence and 
associations of amblygonite at Branchville, Connecticut, see the 
papers by Messrs. Brush an 
n closing I wish to acknowledge my indebtedness to Pro- 
fessor Geo. J. Brush, who has most liberally furnished me with 
the material needed for this examination. 
Sheffield Laboratory, June 18, 1879. 
, Agr. XL.—On the fs a ee of Glacial Drift upon Resid- 
uary Clays; by W. J. McGEE. 
THE accompanying actual section is exposed in a cut on 
the Delaware & St, Paul Railroad, a mile north of Delaware, 
Delaware County, Iowa. No. 1 is glacial drift, somewhat light 
2 oe 
and sandy, but containing erratics and continuous with the 
mantle of “sround moraine” deposits covering the greater por- 
* This Journal, July and August, 1878, and May, 1879. 
