ISLE OF

PORTLAND  , properly a peninsula of the coast of Dorsetshire, England, as a prolongation of a narrow ridge of shingle, Chesil Bank (q.v.), connects it with the mainland . Pop . (1901), 15,262 . It is 4 M. long and nearly 11 in extreme breadth, with an area of about 41 sq. m . The shores are wild and precipitous, and Portland is inaccessible from the sea except towards the south . The highest point, close upon 500 ft., is the Verne hill in the north . Wave action is seen in the numerous caverns, and south-east of Portland Bill, the southern extremity of the isle, is a bank called the Shambles, between which and the land there flows a dangerous current called the Race of Portland . A raised beach is seen at Portland Bill . The substratum of the island is Kimeridge Clay, above which rests beds of sand and strata of Oolitic limestone, widely famed as a building stone . Extensive quarries, which are Crown property, have supplied the materials for St Paul's Cathedral and many other important public buildings . In the " dirt-bed " resting upon the Oolitic strata numerous specimens of petrified wood are found, some of great size . The soil, though shallow, is fertile, and mutton fed on the grass has a peculiar rich flavour .

Quarrying, fishing and agriculture are the chief industries . Several curious local customs are retained by the inhabitants . A joint railway of the Great Western and London & South Western companies runs south from Weymouth to Portland (44 m.) and Easton (82 m.) on the isle . The isle contains a convict prison with accommodation for about 1500 prisoners . Portland Castle, built by Henry VIII. in 1520, is generally occupied by the commander of the engineers or of the regiment stationed on the island . On a rock on the eastern side are remains of a more ancient fortress, Bow and Arrow Castle, ascribed to William Rufus . A harbour of refuge, begun in 1847 under the direction of the Admiralty, was completed some fifteen years later . A breakwater stretching in a northerly direction from the north-east corner of the island partially enclosed a large area of water naturally sheltered on the south and west . An inner arm ran nearly east from the island and terminated in a masonry head and fort, and an outer detached arm bent to the north and terminated in a circular fort, a narrow entrance for shipping being left between the two . It was formed of a rubble mound quarried by convict labour at the summit of the island, and was lowered by a wire-rope incline to the sea . The harbour thus made was open on the north to Weymouth and the Channel, but the necessity for greater protection from torpedo attack made it advisable to complete the enclosure . Accordingly the Naval Works Acts of 1895 and subsequent years sanctioned works for closing the gap—about 2 m. long—between the end of the outer breakwater and the Bincleaves rocks near Weymouth, by two new breakwaters .

One of these runs nearly east from the Bincleaves

shore and is about 4642 ft. long, while from its extremity the other, about 4465 ft. long, stretches in a south-east direction towards the old outer breakwater, passages for navigation about 700 ft. wide separating it from its neighbours at each end . These new structures also consist of rubble mounds . The defensive harbour thus completely enclosed has an area of 2200 acres to the one-fathom line, of which 15oo acres have a depth of not less than 3o ft. at low water . There is no dockyard at Portland, but the watering and coaling arrangements for the supply of the fleet are of considerable importance . There is a coaling jetty and camber for the storage of both sea-borne and land-borne coal, with hydraulic appliances for handling it . The harbour and island are strongly fortified . The isle of Portland is not mentioned in the time of the Romans . In 837 it was the scene of an action against the Danes, and in 1052 it was plundered by Earl Godwine . In 1643 the parliamentary party made themselves masters of the island and castle, but shortly afterwards these were regained by the Royalists through a clever stratagem, and not recovered again by the forces of the parliament till 1646 .