A geometrical fit of the land masses of northern Europe, Canada and Greenland has been constructed by Dr A. G. Smith using the method devised by Sir Edward Bullard and Mr J. E. Everett. The method involves taking points of latitude and longitude on the 500 fm. line at intervals of about 30 miles along the two coasts to be fitted. Young features such as oceanic islands are ignored. By a method of successive approximation, the computer `homes in' on to the centre of rotation which gives the minimum root mean square misfit between the rotated coastlines; the misfit being measured as the discrepancy of longitude relative to the centre of rotation. In this manner the 500 fm. line along the east coast of Greenland has been fitted to that of northwestern Europe to form one unit. This unit, that is, the 500 fm. line of the west coast of Greenland and the Channel approaches have been fitted on to the 500 fm. line of Canada. Maps of this fit drawn as a conical projection with two standard parallels of latitude will be presented and will show the geochronological patterns across the reconstructed land masses.