As to the date of this trade we can say little with certainty at present. We have seen that objects have been found in Spain which seem to point to a connection with Hissarlik II. In the temple of Hal Tarxien in Malta were found certain carved stones with a double spiral ornament[146], which exactly resemble some in the Syracuse museum, which had closed some of the rock-cut tombs near that city.[147] These tombs have been relegated by Signor Orsi to the period he calls Siculan I., and to this period belong the rock-cut tombs at Castellucio, in one of which was found several pieces of carved ivory, which closely resemble a piece found in Hissarlik II[148]. This city was founded about 2500 /B.C./, or perhaps some centuries earlier, and seems to have been sacked about 2225 /B.C./[149] The trade then which we are discussing must have taken place during the latter half of the third millennium /B.C./, and in the light of the Babylonian tablet already quoted may well have begun some centuries earlier. How soon the trade and the megalith cult passed on from Spain to Brittany and thence to Ireland and the Baltic is uncertain, though it becomes difficult to fit in all the successive cultures unless we postulate that megalithic monuments were known in Denmark and the south of Sweden as early as 2400 or 2500 /B.C./[150]; in Brittany a still earlier date seems to be needed. We may then suggest tentatively that the Atlantic trade began before the close of the first half of the third millennium. All this seems to indicate that the rock-cut tomb with an antechamber, the fore-runner of the dolmen, came from Asia; the antechamber also occurs in the Egyptian _mastaba_. Professor Elliot Smith believes that this structure, and the use of the antechamber, developed in Egypt,[151] but of this I do not feel confident. It may well have been introduced into that land from the north-east by his Giza folk. If these may be identified, as I think they may, with Newberry’s people, who introduced wheat and the second pre-dynastic culture, we must postulate the use of rock-cut tombs with antechambers in Syria before 4000 /B.C./ Rock-cut tombs and dolmens, dating from before and just after the discovery of metal, are not uncommon in some parts of this region.[152]