Sado, which issues into Setubal Bay, is the only important river of this region. North of the Tagus, and parallel with its right bank, extends the mountain chain which is known at its northern extremity as the Serra do Aire and, where it terminates above Cape da Roca, as the Serra da Cintra. This ridge, which is buttressed on all sides by lesser groups of hills, and includes part of the famous lines of Torres Vedras (q.v.), exceeds 2200 ft. in height, and constitutes the watershed between the right-hand tributaries of the Tagus and the Liz, Sizandro and other small rivers which flow into the Atlantic. On its seaward side, except for the line of sheer and lofty cliffs between Cape Carvoeiro and Cape da Roca, the country is mostly flat and sandy, with extensive heaths and pine forests; but along the fertile and well-cultivated right bank of the Tagus the river scenery, with its terraced hills of vines, olives and fruit trees, often resembles that of the Rhine in Germany. The natural resources of Portuguese Estremadura, with its inhabitants, industries, commerce, communications, &c., are described under Portugal; for on such matters there is little to be said of this central and most characteristic province which does not apply to the whole kingdom. Separate articles are also devoted to Lisbon, the capital, and Abrantes, Cintra, Leiria, Mafra, Santarem, Setubal, Thomar, Torres Novas and Torres Vedras, the other chief towns. The women of Peniche, a small fishing village on the promontory of Cape Carvoeiro, have long been celebrated throughout Portugal for their skill in the manufacture of fine laces.
2. Spanish Estremadura is bounded on the N. by Leon and Old Castile, E. by New Castile, S. by Andalusia, and W. by the Portuguese province of Beira and Alemtejo, which separate it from Portuguese Estremadura. Pop. (1900) 882,410; area, 16,118 sq. m. Spanish Estremadura consists of a tableland separated from Leon and Old Castile by the lofty Sierra de Gredos, the plateau of Béjar and the Sierra de Gata, which form an almost continuous barrier along the northern frontier, with its summits ranging from 6000 to more than 8500 ft. in altitude. On the south the comparatively low range of the Sierra Morena constitutes the frontier of Andalusia; on the east and west there is a still more gradual transition to the plateau of New Castile and the central plains of Portugal. The tableland of Spanish Estremadura is itself bisected from east to west by a line of mountains, the Sierras of San Pedro, Montanchez and Guadalupe (4000–6000 ft.), which separate its northern half, drained by the river Tagus, from its southern half, drained by the Guadiana. These two halves are respectively known as Alta or Upper Estremadura (the modern Cáceres), and Baja or Lower Estremadura (the modern Badajoz). The Tagus and Guadiana flow from east to west through a monotonous country, level or slightly undulating, often almost uninhabited, and covered with a thin growth of shrubs and grass. Perhaps the most characteristic feature of this tableland is the vast heaths of gum-cistus, which in spring colour the whole landscape with leagues of yellow blossom, and in summer change to a brown and arid wilderness.
The climate in summer is hot but not unhealthy, except in the swamps which occur along the Guadiana. The rainfall is scanty; dew, however, is abundant and the nights are cool. Although the high mountains are covered with snow in November, the winters are not usually severe. The soil is naturally fertile, but drought, floods and locusts render agriculture difficult, and sheep-farming is the most important of Estremaduran industries. (See Spain: Agriculture.) In the 19th century, however, this industry lost much of its former importance owing to foreign competition.
Immense herds of swine are bred and constitute a great source of support to the inhabitants, not only supplying them with food, but also forming a great article of export to other provinces—the pork, bacon and hams being in high esteem. The beech, oak and chestnut woods afford an abundance of food for swine, and there are numerous plantations of olive, cork and fruit trees, but a far greater area of forest has been destroyed. For an account of commerce, mining, communications, &c., in Spanish Estremadura, with a list of the chief towns, see Cáceres and Badajoz. In character and physical type, the people of this region are less easily classified than those of other Spanish provinces. They lack the endurance and energy of the Galicians, the independent and enterprising spirit of the Asturians, Basques and Catalans, the culture of the Castilians and Andalusians. Their failure to develop a distinctive local type of character and civilization is perhaps due to the adverse economic history of their country. The two great waterways which form the natural outlet for Estremaduran commerce flow to the Atlantic through a foreign and, for centuries, a hostile territory. Like other parts of Spain, Estremadura suffered severely from the expulsion of the Jews and Moors (1492–1610), while the compensating treasure, derived during the same period from Spanish America, never reached a province so remote at once from the sea and from the chief centres of national life. Although Cortes (1485–1547), the conqueror of Mexico and Pizarro (c. 1471–1541), the conqueror of Peru, were both born in Estremadura, their exploits, far from bringing prosperity to their native province, only encouraged the emigration of its best inhabitants. Heavy taxation and harsh land-laws prevented any recovery, while the felling of the forests reduced many fertile areas to waste land, and rendered worse a climate already unfavourable to agriculture. Few countries leave upon the mind of the traveller a deeper impression of hopeless poverty.
ESTREMOZ, a town of Portugal, in the district of Evora,
formerly included in the province of Alemtejo; 104 m. by rail
E. of Lisbon, on the Casa Branca-Evora-Elvas railway. Pop.
(1900) 7920. Estremoz is built at the base of a hill crowned
by a large dismantled citadel; its fortifications, which in the
17th century accommodated 20,000 troops and rendered the
town one of the principal defences of the frontier, are now obsolete.
There are marble quarries in the neighbourhood, and the Estremoz
bilhas, red earthenware jars, are used throughout Portugal as
water-holders and exported to Spain. At Ameixial (1188) and
Montes Claros, near Estremoz, the Spanish were severely defeated
by the Portuguese in 1663 and 1665. Villa Viçosa (3841), 10 m.
S.E., is a town of pre-Roman origin, containing a royal palace.
The altars with Latin inscriptions to the Iberian god Endovellicus,
found at Villa Viçosa, are preserved in the museum of
the Royal Academy of Sciences, Lisbon.
ESTUARY (from the Lat. aestuarium, a place reached by
aestus, the tide), an arm of the sea narrowing inwards at the
mouth of a river where sea and fresh water meet and are mixed,
i.e. the tidal portion of a river’s mouth. Structurally the estuary
may represent the long-continued action of river erosion and
tidal erosion confined to a narrow channel, most effective where
most concentrated, or an estuary may be the drowned portion of
the lower part of a river-valley. In a map of Britain showing
sea-depths it will be observed that under the Severn estuary the
sea deepens in a number of steps descending by concentric V’s
that become blunter towards deep water until the last is a mere
indentation pointing towards the long narrow termination of
the present estuary. In this and in similar cases the progress of
the estuary is indicated upon what is now the continental shelf.
The chief interest in estuarine conditions is the mingling of sea
and fresh water. Where, as in the Severn and the Thames, the
fresh water meets the sea gradually the water is mixed, and there
is very little change in salinity at high tide. The fresh water
flows over the salt water and there is a continuous rapid change
in salinity towards the sea, for the currents sweeping in and out
mix the water constantly. Where the river brings down a great
quantity of fresh water in a narrow channel, the change of
salinity at high and low water is very marked. “When, however,
the inlet is very large compared with the river, and there is no
bar at the opening, the estuarine character is only shown at the
upper end. In the Firth of Forth, for example, the landward
half is an estuary, but in the seaward half the water has become
more thoroughly mixed, the salinity is almost uniform from
surface to bottom, and increases very gradually towards the
sea. The river-water meets the sea diffused uniformly through
a deep mass of water scarcely fresher than the sea itself, so that
the two mix uniformly, and the sea becomes slightly freshened
