R. P. Stevens— Glaciers of the Glacial Era in Virginia. 871 
Two of the filtrates and one of the washwaters were ex- 
amined for arsenic acid. One filtrate and washwater were acidi- 
fied with chlorhydric acid, and saturated with sulphuretted- 
hydrogen. After allowing to stand 20 hours, no precipitate 
was formed. The other filtrate above mentioned was treated 
with a large excess of magnesium mixture and warmed; the 
precipitate of magnesic hydrate or carbonate which was formed 
was filtered and redissolved in a very small quantity of chlor- 
ydric acid. On the addition of an excess of ammonic 
hydrate, no precipitate was obtained. It appears from these 
experiments that arsenic acid can be completely precipitated . 
y employing an alcoholic solution of chloride of magnesium, 
and that the precipitate can be ignited without danger from 
loss by reduction, after the ammonia which it contains has 
been transformed into the nitrate by the addition of nitric acid. 
Art. XLI.—On Glaciers of the Glacial Era in Virginia ; by 
R. P. Stevens. (From a letter to one of the Editors.) 
and south. : 
Other than these signs were seen at the new opening upon 
e middle vein, on lands of the James River Coal Co., lying 
ad previously noticed similar phenomena south of James 
River. That the Richmond coal field had been struck by a 
moving glacier was quite as palpable as the northern fields 
of Pennsylvania. Richmond is in latitude 37° 30 
time for examination, I soon found in the railroad cuts the ve 
turned edges of bluish slates shaved off, with drift clays an 
