Lithology: It primarily consists of tillite or diamictite, which is a poorly sorted, matrix-supported sedimentary rock. It contains a diverse array of angular to sub-rounded clasts (boulders, cobbles, pebbles) within a finer-grained, often argillaceous or sandy matrix. These clasts are typically lithologically varied, including quartzite, limestone, granite, and schist, reflecting their origin from various bedrock sources. Some clasts exhibit faceted or striated surfaces, characteristic of glacial transport.

Type Locality: The formation derives its name from the Blaini section near Mussoorie, Uttarakhand, in the Lesser Himalayan region of India, where it is well-exposed.

Age: It is unequivocally assigned to the Late Proterozoic (Neoproterozoic) Era, specifically correlated with the Cryogenian Period, roughly 700-600 million years ago.

Depositional Environment: The Blaini Boulder Bed represents a glacial or glaciomarine environment. Its characteristics point to deposition directly from glaciers (till) or by icebergs melting in shallow marine settings (glaciomarine diamictite), indicative of a widespread, significant period of glaciation.