This site provides evidence of multiple social groups occupying the same village but using different pottery and living in different types of houses: "over time the Late Harappan pottery was gradually replaced by Painted Grey ware pottery," and other cultural changes indicated by archaeology include the introduction of the horse, iron tools, and new religious practices. There is also a Harappan site called Rojdi in Rajkot district of Saurashtra. Its excavation started under an archaeological team from Gujarat State Department of Archaeology and the Museum of the University of Pennsylvania in 1982–83. In their report on archaeological excavations at Rojdi, Gregory Possehl and M.H. Raval write that although there are "obvious signs of cultural continuity" between the Harappan Civilisation and later South Asian cultures, many aspects of the Harappan "sociocultural system" and "integrated civilization" were "lost forever," while the Second Urbanisation of India (beginning with the Northern Black Polished Ware culture, c. 600 BCE) "lies well outside this sociocultural environment". Previously, scholars believed that the decline of the Harappan civilisation led to an interruption of urban life in the Indian subcontinent. However, the Indus Valley Civilisation did not disappear suddenly, and many elements of the Indus Civilisation appear in later cultures. The Cemetery H culture may be the manifestation of the Late Harappan over a large area in the region of Punjab, Haryana and western Uttar Pradesh, and the Ochre Coloured Pottery culture its successor. David Gordon White cites three other mainstream scholars who "have emphatically demonstrated" that Vedic religion derives partially from the Indus Valley Civilisations.  , archaeological data suggests that the material culture classified as Late Harappan may have persisted until at least c. 1000–900 BCE and was partially contemporaneous with the Painted Grey Ware culture. Harvard archaeologist Richard Meadow points to the late Harappan settlement of Pirak, which thrived continuously from 1800 BCE to the time of the invasion of Alexander the Great in 325 BCE. In the aftermath of the Indus Civilisation's localisation, regional cultures emerged, to varying degrees showing the influence of the Indus Civilisation. In the formerly great city of Harappa, burials have been found that correspond to a regional culture called the Cemetery H culture. At the same time, the Ochre Coloured Pottery culture expanded from Rajasthan into the Gangetic Plain.