This model predicts that all three units-namely, the Lesser Himalayan, Greater Himalayan, and Tethyan Himalayan-must have a nearly identical depositional age and depositional setting, and are derived from similar sources. Immediately, primary evidence from detrital zircon ages, paleocurrent recorded in the units, and animal similarities supports these predictions. Firstly, the detrital zircon data for the Lesser Himalaya and Tethyan Himalaya sequence yield similar age spectra when similar aged samples were used. Furthermore, when samarium-neodymium dating of the entire North Indian sequence was made, significant overlap of Nd isotopic signatures between the different rocks units indicates a sharing of similar sources.