Classical works on Indian stratigraphy described three stratigraphic units, viz., Subathu, Dagshai and Kasauli within the Tertiary sequence of Simla Hills, India. Present work shows that the above three units represent mostly intertonguing among three distinct lithofacies, respectively termed as green, red and grey facies depending upon the dominant shale colour. Environmental significance of each facies is discussed. A road log presenting evidences of facies intertonguing on the basis of sedimentary structures is described.