25/27 A slight depression of the surface, or some local or accidental check of some drainage-course, or any other similar and trivial cause, may have laid them under water. The process of silicification proceeded gradually but steadily, and after they had there, in lapse of ages, become lapidified, the next outburst of volcanic matter overwhelmed them, broke them, partially enveloped, and bruised them, until long subsequent denudation once more brought them to light' (J.G.Medlicott, in _Memoirs of the Geological Survey of India_, vol.ii.Part II, pp. 200, 203, 204, 205, 216, as quoted in _C. 435). |