176 GEOLOGICAL RECONNOISSANCE 
might become useful as a common paint, though the amount of oxide of 
iron present is rather small. 
No. 36. Argillaceous rock, from the crevices of the New York company’s 
lead mines, Marion county. . 
Massive, amorphous; color pale yellowish-white and reddish-white; 
very light and soft; can be cut with a knife like chalk; on the surface, 
covered with a crust of peroxide of iron; powder of a pale reddish cream 
color; assumes on ignition a fine pink color. 
Composition, dried at 230 deg. F: 
Insoluble silicates, mainly a very fine soft clays ++++++s+se+- 96.095 
Peroxide of iron, and alumina, with a little phosphoric acid. 1.795 
Lh eee Terre ee eevee eee er Te see 0.148 
Manganese, magnesia, and potassa----+--+-. serene ences traces 
Water sr rcr cere eves esnvcccrevee reser erercrsreresercece 2.055 
100.093 
The air-dried rock lost 0.73 per cent. of moisture, at 230 deg. F. 
No. 37. Argillaceous rock, associated with galena, at Houghton’s dig- 
gings, Lawrence county. 
Bears a great resemblance to the preceding rock in general appearance. 
Its origin is probably the same, occurring, as it does, under similar condi- 
tions; butit appears to have come in contact, after its deposition, with liquids 
containing oxide of zinc in solution. The presence of about 8 per cent. 
of oxide of zinc in this clay points to the deposition of carbonate of zinc 
somewhere near Houghton’s lead diggings. 
Massive, amorphous; color ochre-yellow; light and soft; can be cut with 
a knife like chalk; covered on the surface with a thin layer of red clay, 
resembling No. 35; powder of a dirty grayish-yellow color. 
Composition, dried at 230 deg. F: 
Clay and sand-+++sseeeeeeeeeeee ee eee 74,841 
Peroxide of iron. -seeesese eects eccvcecuece 2.383 
Alu Miia Sie ORs wae aniee ei he Mie ee Aas 8.213 
Phosphoric acid. +++++sseeeeeeeeeeeeeeaeeee 0.214 
Oxide of zinc, with trace of manganese----+- 8.262 
Carbonate of lime+ ++ ++ e eee secre cece cane ss+ 0.709 
Carbonate of magnesia.-...+.... seeeeeeeee 1,387 
Water and carbonic acid (?), expelled by Heats 3.844 
99.803 
The air-dried clay lost 3.92 percent. of moisture at 230 deg. F. 
