Professor Forbes stated that Mr Milward's shrewd suspicion of the bands of ice of different consistence being accompanied also by wrinkles or elevations, had been discovered by himself some years before, at the very place and time pointed out as most likely; and he shewed that, while there is a tendency in a tenacious viscous fluid to produce wrinkles, under pressure capable of effecting detrusion, even where the supply of the fluid is uniform; that this quality is greatly increased when the supply of the fluid is by fits, as it is in fact at the head of this glacier, where the quasi-hydrostatic pressure from behind, combined with the frontal resistance, produces a thickening, or convex lip or wrinkle.