This makes an excellent foundation. Loam, when mixed with other earthy substances, and when compact and of considerable depth, is a good foundation soil. Sand is formed by the decomposition of rocks. It s generally found in beds, which were, at one time, riverbeds. It isn t a good foundation soil unless it s well combined and well drained.
Quicksand is very fine sand mixed with loamy materials, which retains a large quantity of water.
It s very poor foundation soil, as it will flow into the excavation as fast as it can be dug out. Quicksand can be prepared for foundations only with great difficulty and expense. Marshy soils are formed by the decay of plants and other vegetable matter in sluggish water. Since there s no current, the plants take root in the bed. Successive beds of decayed plants are formed under slight pressure, and small cavities are formed.