Harappa's rich historical artifacts, many lying half-buried. In 1842, Masson included his observations of Harappa in the book Narrative of Various Journeys in Baluchistan, Afghanistan, and the Punjab. He dated the Harappa ruins to a period of recorded history, erroneously mistaking it to have been described earlier during Alexander's campaign. Masson was impressed by the site's extraordinary size and by several large mounds formed from long-existing erosion. Two years later, the Company contracted Alexander Burnes to sail up the Indus to assess the feasibility of water travel for its army. Burnes, who also stopped in Harappa, noted the baked bricks employed in the site's ancient masonry, but noted also the haphazard plundering of these bricks by the local population. Despite these reports, Harappa was raided even more perilously for its bricks after the British annexation of the Punjab in 1848–49. A considerable number were carted away as track ballast for the railway lines being laid in the Punjab. Nearly of railway track between Multan and Lahore, laid in the mid 1850s, was supported by Harappan bricks. In 1861, three years after the dissolution of the East India Company and the establishment of Crown rule in India, archaeology on the subcontinent became more formally organised with the founding of the Archaeological Survey of India (ASI). Alexander Cunningham, the Survey's first director-general, who had visited Harappa in 1853 and had noted the imposing brick walls, visited again to carry out a survey, but this time of a site whose entire upper layer had been stripped in the interim. Although his original goal of demonstrating Harappa to be a lost Buddhist city mentioned in the seventh century CE travels of the Chinese visitor, Xuanzang, proved elusive, Cunningham did publish his findings in 1875. For the first time, he interpreted a Harappan stamp seal, with its unknown script, which he concluded to be of an origin foreign to India. Archaeological work in Harappa thereafter lagged until a new viceroy of India, Lord Curzon, pushed through the Ancient Monuments Preservation Act 1904, and appointed John Marshall to lead the ASI. Several years later, Hiranand Sastri, who had been assigned by Marshall to survey Harappa, reported it to be of non-Buddhist origin, and by implication more ancient. Expropriating Harappa for the ASI under the Act, Marshall directed ASI archaeologist Daya Ram Sahni to excavate the site's two mounds. Farther south, along the main stem of the