Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/202

 occur in the lateral action of rivers on the alluvia of vallies; on the banks of the Tay and in many others of the principal rivers of Scotland. Greater effects have often been attributed to the corrosive powers of the sea, and in indulging this speculation I have kept far within the range commonly occupied by geologists. I may remark that the narrowness of the channel, which in one part does not exceed a quarter of a mile, and the shallowness of the soundings compared with the depth of those which separate the other parts of Sky from the main land, are friendly to this supposition. These scarcely exceed ten fathoms in the middle, although there are some deeper holes on each side ranging to thirteen, the bottom being every where gravelly, as if, like the banks, it was the remains of some former alluvium.