10 
Class I. 
Order III. 
AGGREGATES. 
Sp. 2. Clay. 
This consists of common clay mixed with decayed ve 
getable and animal substances. 
Sp. 3. Loam. 
Any soil which does not cohere so strongly as clay, 
but more strongly than chalk, is called loam. There 
are many varieties of it. The following are the most 
common. 
Variety 1. Clayey loam; called also strong, stiff, cold, 
and beavy loam.—It consists of a mixture of clay and 
coarse sand. 
Variety 2. Chalky loam.—A mixture of clay, chalk, 
and coarse sand ; the chalk predominating 
Variety 3. Sandy loam.—A mixture of the same 
ingredients ; the sand amounting to .8 or .9 of the 
whole. 
Sp. 4. Till. 
Till is a mixture of clay and oxide of iron. It is of 
a red colour, very hard and heavy. 
SECT. II. 
AGGREGATES OF AMORPHOUS STONES. 
HE aggregates which belong to this section consist 
of amorphous fragments of stones cemented together. 
They may be reduced to the following genera : 
1. Sandstone, 
2. Puddingstone, 
3. Amygdaloid, 
4. Breccia.