The Black coloured soil, which is sticky and highly plastic in nature is

→ Gumbo: This is a black coloured soil, which is sticky and highly plastic in nature
→ Bentonite: The clay formed by the chemical weathering of volcanic ash
→ Tuff Soil: This is a fine-grained soil slightly cemented volcanic ash
→ Marl: This material is a combination of clay, loam, and calcareous sands
→ Peat: Fibrous aggregate with decomposed fragments of vegetable matter
→ Loam: This material is a combination of silt, clay, and sand in definite proportion