y 
198 = BB. Silliman—Geological and Mineralogioal Notes 
and is easily reduced toa fine granular non-crystalline powder, 
ile the non-magnesian beds beneath resemble dolomite im 
fracture, though quite free from magnesia. They are non-fos- 
siliferous so far as observed by me. Whether they are strictly 
conformable to the crystalline white limestones is doubtful, 
and further explorations are needful to decide this point, which 
is one of considerable interest in view of their metallurgica 
contents. 
The great chamber of the Emma Mine, which is an ovoidal 
cavity measuring, so far as explored, about 110 feet vertical by 
about 80 by 110 feet transverse, was found to be filled almost 
exclusively with epigene species, the product of oxidation of 
sulphides, and maak By of removal without the aid of gunpowder, 
for the most part. The study of this mass reveals the interest- 
ing fact that it is very largely composed of metallic — = 
pe 
Mitek once eee aye ee 0°48 
CAG, 555-2 ole 84°14 Atuming, . 2.2.1. 55 -<-- 8 a 
prepare ese ee 2°37 Mapnesia,.. >. ---,----+"<"" 0.2 
Antimony,.--- ---- Pere Name i) eee 0-72 
Copper: i S55 0°83 Carbonic acid,..----------- ie 
BIG cl CIES 2°92 90°42 
Manganese, -_.-._. O15 Oxygen and water by diff, 9°58 
-Os te ui wets 3°54 — 
100°00 
The quantity of silyer obtained from this lot of ore was 156 
troy ounces to the gross ton of 2240 pounds. : 
his analysis sheds important light on the chemical history 
of this remarkable metallic deposit, and will aid us in the dy 
‘of the paragenesis of the derived species. It is pretty, certain 
