Several causes have contributed to the decay of the Devonshire ports. Most of them are situated on river-estuaries which, in the lapse of ages, have become silted up by mud and sand brought down by the rivers, or obstructed by shingle washed up by the waves. The harbour of Sidmouth was destroyed by the encroachment of the sea and the fall of the cliffs which formerly protected it. Again, the tonnage of ships, and consequently the amount of water they draw, have very greatly increased since Tudor and Stuart times, when these ports were in their prime; and it would be impossible for the large vessels of to-day to navigate the shallow and danger-strewn waters of our estuaries, even if they could cross the bars by which they are obstructed. Nor is it worth while to improve the navigation by dredging, as is done to so great an extent on the Thames, the Mersey, and the Clyde. The industries of Devonshire are now of small importance, and the county has no great manufacturing centres to supply freights. Plymouth Sound is the only busy waterway, and Plymouth is the one populous town requiring large quantities of imports. The only harbour in North Devon given in the shipping returns is Barnstaple, with which are associated Ilfracombe, Bideford, and Appledore. Ilfracombe, the only port in the long stretch of coast between Bridgwater and Padstow, had formerly a good deal of traffic with Wales and Ireland, but its tidal harbour is now visited only by excursion steamers and small coasting-vessels. The other three towns are river-ports. Barnstaple is eight miles from the mouth of the Torridge, Appledore is just inside the entrance of the Taw, and Bideford is five miles up the same river, whose estuary is obstructed by a dangerous bar, only to be crossed at high tide. In the sixteenth and seventeenth centuries all three towns had an active trade with North America; and even in comparatively recent times ships of 1000 tons have been moored at Barnstaple quay. But at the present day only 37 cargo-carrying vessels sail to and from the whole group in a year, and the trade (chiefly in timber and dye-stuffs) of all four together, principally with home ports, but also with Sweden and Norway and some other European countries, amounts to little more than £18,000 in twelve months. Dartmouth, Brixham, and Salcombe form another group of ports, all of which have played a part in history. Their total trade, the import of timber and the export of ships and boats, amounts to nearly £19,000 a year, and such foreign intercourse as they have is chiefly with Sweden, Norway, and Russia. Exeter and Exmouth, with which is associated Lyme Regis in the adjoining county of Dorsetshire, rank next in importance, Topsham, the ancient port of Exeter, having gone entirely to decay. Their annual trade, about half of which consists of wood, cured fish, and sugar, and which, as regards foreign intercourse, is mainly with France, Germany, and Sweden, is nearly £100,000.