Occurrence of Clay Minerals in Nature

Clay minerals are the chief constituents of clays, and they also occur in significant proportions in other earth materials, as illustrated in Fig. 1.4. The 

Boulder Cobble Pebble Granule Sand SIR Clay 

The soil layer is imderlain by a layer of imconsolidated sediments and rock fragments (regoliths). The classification of sediments based on grainsize is given in Table 1.3. Majority of clay-sized sediments are clay minerals. 

---