No abstract

Dholavira is a Harappan city in Gujarat, India whose fortification, with maximum wall thickness of up to 18 m is extraordinary. The probable cause of such a massive protective wall is yet to be addressed. Based on (i) the location of Dholavira along tsunami/stormprone coast; (ii) climatic scenario during the midHolocene with special reference to higher sea level and (iii) lack of proto-historic military evidences, we hypothesize that the walls may have acted as defence against tsunami/sea storm. The presence of extremely thick protective walls thus implies that the Dholavirans were probably aware of the magnitude of destruction caused by tsunami waves/storms.

India had a very active maritime trade contact with the Roman world between the 4th century BC and the 4th century AD. In this context recent finds of stone anchors, potsherds, lead anchors and a lead ingot from 5 to 8 m water-depth near Bet Dwarka jetty is significant. The sherds include amphoras, jars, bowls and lids. Archaeological finds along the Indian coast and comparison between amphoras from Bet Dwarka and the Mediterranean suggest that the artefacts from Bet Dwarka may be datable to between the 1st century BC and the 2nd century AD. The numbers of stone anchors suggests that this was an ancient anchorage.

Various types of lead ingots have been reported from a number of shipwrecks from different parts of the world. In 1991 exploration of a wreck off Poompuhar, Tamil Nadu, East Coast of India, at a depth of 19 m yielded a gun, rudder gudgeon, gunpowder boxes and a variety of lead ingots. The most significant ingots are those marked W: Blackett and D with a crown symbol on the obverse and 1791, 1792 and some merchant marks on the reverse. These are similar to Blackett lead ingots found in England, the Netherlands and Sumatra. Pb-isotopic analysis has revealed their source as the North Pennine lead mines of England. Further, the lead used was of high purity -93%. Records show that Blackett was a well-known lead-exporting company in England since 1694. The wreck off Poompuhar may be a Toni type cargo ship carrying traded lead ingots of different manufacturers.