A tale of two rocks - the unconformity of tuff and conglomerate-Here you can see two types of rock different in colour and texture in contact. This is called unconformity. The two types of rock here are tuff and conglomerate, which are igneous rock and sedimentary rock.

Igneous rock is formed from solidified magma, when magma is ejected during volcanic eruption, the igneous rock thus formed can be called volcanic rock. Tuff is formed from volcanic ash ejected into the atmosphere but which eventually settled into the ground surface. It has a fine texture. The location of the volcano which produced these tuffs has not yet been identified.

Sedimentary rock is formed by the accumulation and consolidation of sediments. Conglomerate is a kind of sedimentary rock characteristically composed of rounded pebbles cemented by sand and mud. Since the sediments are mostly brought down from the upstream parts of rivers, you can see why the edges of pebbles in conglomerate are rounded!

plain why the edges and corners of pebbles in conglomerate are rounded!