“141 
TAB. CCLXXI. 
PLUMBU M_  sulphureum. 
Sulphuret of Lead, or Galena. 
Div. 1. Crystallized. 
ee 
‘Tue Galena, or Sulphuret of Lead, is remarkably striking 
in this figure, not only because it is eight times repeated in 
stripes, but the coincidence of the opposite halves is pecu- 
liar; the outer stripes are nearly of the same width, and the 
next within them double, and those again nearer the middle 
are single, and nearly the same width, so that the whole - 
together form eight lines in pairs. The substance in the 
middle of the specimen is Sulphate of Barytes, and ‘the 
substance between the lines of Sulphuret of Lead is Car- 
bonate of Lime; there is some Sulphate of Barytes on the 
outer sides. } 
The specimen came from Derbyshire. I know not in 
what position it was found, whether lying horizontally, per- 
pendicularly, or obliquely; it, however, has been admired 
as a remarkable stratification by some, and as an example 
of a vein by others, instancing what Dr. Thomson says of 
a vein according to Werner, where it is- understood as 
characteristic of a vein to have opposite sides alike, with 
ihe same or different substances often repeated. The lower 
pair of double stripes differ from the upper in this specimen, 
by haying a more regular and equally bounded zigzag line 
between them. 
The lower figure is Sulphate of Strontian from Bristol, 
bounded by Sulphuret of Lead, 
