35G 
COMPOSITION OF SHALES, 
the decomposed mica slates have been already thus employed. Dr. Jackson, in his New- 
Hampshire Report, gives the analysis of one which experience has proved valuable in this 
way by mixing its debris in a compost of peat, lime, etc. 
ANALYSIS BY DR. JACKSON. 
Water_ 3*6 
Vegetable matter_ 1 *8 
Silica_ 79-2 
Peroxide of iron and alumina_ 5*6 
Potash_ 2*2 
Soda_ 2 *5 
Lime_ 3-2 
Magnesia_ 1*2 
99-3 
The composition of this primary slate may be compared with the taconic slates. We do 
not, however, mean to convey the impression that slates and shales are definite chemical 
compounds ; and yet there is little doubt but that analysis gives their general constitution, 
and that they will not be found to vary excessively from the composition which we have 
found them to possess. 
COMPOSITION OF THE SLATES AND SHALES OF NEW-YORK AND OTHER PLACES. 
NAMES. 
Water and 
organic 
matter. 
Silica. 
Peroxide of 
iron and 
alumina. 
Carbonate 
of lime. 
Magnesia. 
Phosphates 
Potash. 
Sulphate 
of lime. 
Hoosic roofing slate. 
3-79 
70*55 
20*35 
0*99 
0*40 
trace. 
3*32 
Slate from Salem... 
2-62 
84*65 
11*53 
0*60 
0*60 
trace. 
Waterville, Me. 
3-42 
71*62 
23*25 
0*10 
0*05 
0*90 
1*52 
Fairhaven .. 
2-70 
80*72 
12*76 
1*76 
0*40 
* 
Welch roofing slate. 
2-64 
78*76 
16*64 
0*36 
0*52 
* 
Shale from Cortlandville. 
3-03 
83*50 
12*56 
0*61 
0*30 
trace. 
.. i 
.. 
Cauda galli grit. 
6-00 
81*54 
7*00 
1*76 
trace. 
Marcellus slate. 
4-25 
48*12 
10*00 
36*60 
1*00 
Red slate or shale of the salt group. 
6-48 
68*86 
14*98 
9*89 
0*40 
0*14 
Green shale of the salt group. 
5'56 
34*56 
13*36 
43*06 
2*17 
1*06 
* Loss may be set down as potash and the phosphates probably. 
Clays of new-yoek. 
Clays are highly important materials in the constitution of soils. They are also im¬ 
portant fertilizers, especially when they contain lime, magnesia and potash ; but they are 
more valuable in pottery and brick making. Some kinds of clay, as is well known, enter 
into the composition of the finest works of art — the porcelain ware. The expense of 
moving clay may be considered as the great bar to its use as a fertilizer, and yet its effects 
are most decided upon all lands which are denominated light. 
The Albany or Tertiary clay extends through the vallies of the Champlain and the 
