The Isle of Man situate in the midst of the Irish Sea as an intermediate station between Ireland and Cumbria, North Wales and Galloway, has naturally played a considerable part in various phases of western British life in which coastwise maritime movements have had significance. The phase or phases of megalithic construction included, as is generally agreed, a considerable amount of maritime movement along the coasts of western Britain, and monuments of various types were set up. It may be stated at the outset that, since developments even as late as the introduction of Christianity show relations with megaliths, we are not justified, without special local evidence, in ascribing particular megaliths necessarily to an early period, though there is widespread agreement that some must have been in existence at about 2000 B.C., and even possibly earlier.