Between the later part of the seventeenth century and the beginning of the nineteenth century a number of observers, notably Ray, Strachey, Williams and Smith, contended that the predominant easterly dip of strata in Great Britain was ultimately caused by rotation of the earth. Coal-miners, according to Ray (1692) and Leigh (1700), observed the easterly dip of coal and thought that it shelved in toward the centre of the earth. Miners may also have been responsible for the remark in Atkyns (1712) on the distribution of coal in a meridional belt around the world. John Strachey (1725; 1727), using ideas expressed in Leigh and Atkyns, his own observations on the distribution of strata in Great Britain, and applying William Stukeley's view that the landscape was shaped by rotation of the earth, developed and illustrated a theory of the formation of strata by spin of the earth. John Williams in 1789 also observed the easterly dip of strata and expressed the view that the motion of the earth produced tidal action which progressively built up strata. Finally William Smith in 1801 thought that the strata were formed by chemical precipitation and were curved and distended by the motion of the earth.