At Crieff, in Perthshire, there occurs a series of low hills running parallel to the Grampians. These hills consist of old red sandstone and greywacke. On one of them, the Cnock, the village of Crieff is built. Upon the south-east side of this hill, towards the southern extremity, not far from the summit, there are deposited a number of boulder stones of syenitic granite. The largest of these is called the cradlestone. It is nearly spherical, quite smooth on the surface, and 29 feet in circumference. It has been split in two by lightning, (according to the tradition of the place,) and one of the fragments has made one complete revolution down the hill and then stopped. The weight of this boulder is about 30 tons. The nearest mountains of syenitic granite, are those in the neighbourhood of Bennevis, distant more than 60 miles north-west [...]
In Thomas Thomson’s ‘Outlines of mineralogy, geology and mineral analysis‘ volume 2, 1836.