Jan. 20 ,1923 
Probable Cause of Poisonous Greensand 
225 
Since greensand is a mixture of glauconite, shell marl, and other adher¬ 
ing elements, it was desirable to determine the percentage of glauconite 
in each of the three deposits and test its action upon the growth of plants. 
The separations were made by washing off the light materials in the 
greensand. From the residue containing glauconite and other heavy 
materials the glauconite was separated in a relatively pure state by 
means of a magnet. 3 The washings were evaporated to dryness on the 
steam bath and dried to constant weight in an oven. The results are 
given in Table III. 
Table III. —Mechanical analyses of greensand from New Jersey and Virginia 
Source. 
Weight of 
greensand 
airdried. 
Glauconite. 
Residue. 
Courtland, Va. 
Gin. 
62.3350 
36.8440 
41.8820 
Gm. 
40.3420 
5.4028 
6.4290 
Per cent 
64.72 
14.6 
15.O 
Per cent. 
35-28 
85.40 
85.00 
Newcastle, Va. 
Redbank, N. J. 
From Table III it will be observed that the Courtland greensand con¬ 
tained much the highest percentage of glauconite. 
The chemical composition of the samples of glauconite thus obtained 
and of the untreated toxic greensand is shown in Table IV. 
Table IV. —Comparative analyses of glauconite and toxic greensand 
Glauconite. 
Toxic green¬ 
sand. 
Constituents. 
Courtland, Va. 
Newcastle, Va. 
Red Bank, 
N. J. 
Si 0 2 . 
Per cent. 
5 *- 52 
Per cent. 
49.46 
Per cent. 
48. 26 
Per cent . 
60. 14 
SO3 ... 
.04 
. 02 
. 02 
•53 
CaO . 
. 72 
.24 
2.49 
I. 23 
MgO. 
2 . OO 
4 . IO 
I. 80 
4. IO 
Mn 2 0 3 . 
• 55 
.64 
• 15 
.28 
P 3 O fi 
Trace. 
•51 
I. 64 
Trace. 
Fe 2 0 3 . 
25*37 
24 . 65 
24*95 
20.19 
A 1 2 0 3 ... 
3 * 95 
6.08 
7. 02 
8.06 
Cr 2 0 3 . 
NiO . 
Absent. 
Absent. 
Absent. 
Trace. 
.do . 
.do . 
.do . 
Do. 
Free sulphur . 
.do . 
.do . 
... . .do . 
Do. 
K 2 0 . 
6. 29 
7.10 
7.08 
4.76 
Na *0 . 
•63 
*56 
*47 
• 7 * 
Solutions were made from the various samples of glauconite by digest¬ 
ing with 20 per cent hydrochloric acid until digestion was complete, 
evaporating to dryness, heating to dull red heat, and dissolving the resi¬ 
due in dilute hydrochloric acid. These were made up to 500-cc. volume 
each. 
Fifty cc. of each of these solutions were made neutral with ammonia 
and placed in a 250-cc. Erlenmeyer flask with sufficient distilled water 
* Ashley. George H. notes on the greensand deposits of the eastern united states. In U. S. 
Geol. Survey Bui. 660, p. 37-49. fig- x. pi- 2. 1918. 
