The London & North-Western railway (Chester and Holyhead branch) crosses Anglesey from Llanfairpwllgwyngyll to Gaerwen and Holyhead (Caer Gybi), also from Gaerwen to Amlwch. The staple of the island is farming, the chief crops being turnips, oats, potatoes, with flax in the centre. Copper (near Amlwch), lead, silver, marble, asbestos, lime and sandstone, marl, zinc and coal have all been worked in Anglesey, coal especially at Malldraeth and Trefdraeth. The population of the county in 1901 was 50,606. There is no parliamentary borough, but one member is returned for the county. It is in the north-western circuit, and assizes are held at Beaumaris, the only municipal borough (pop. 2326). Amlwch (2994), Holyhead (10,079), Llangefni (1751) and Menai Bridge (Pont y Borth, 1700) are urban districts. There are six hundreds and seventy-eight parishes.
Mon (a cow) is the Welsh name of Anglesey, itself a corrupted form of O.E., meaning the Isle of the Angles. Old Welsh names are Ynys Dywyll ("Dark Isle”) and Ynys y cedairn (cedyrn or kedyrn; “Isle of brave folk"). It is the Mona of Tacitus (Ann. xiv. 29, Agr. xiv. 18), Pliny the Elder (iv. 16) and Dio Cassius (62). It is called Mam Cymru by Giraldus Cambrensis. Clas Merddin, Y vel Ynys (honey isle), Ynys Prydein, Ynys Brut are other names. According to the Triads (67), Anglesey was once part of the mainland, as geology proves. The island was the seat of the Druids, of whom 28 cromlechs remain, on uplands overlooking the sea, e.g. at Plas Newydd. The Druids were attacked in A.D. 61 by Suetonius Paulinus, and by Agricola in A.D. 78. In the 5th century Caswallon lived here, and here, at Aberffraw, the princes of Gwynedd lived till 1277. The present road from Holyhead to Llanfairpwllgwyngyll is originally Roman. British and Roman camps, coins and ornaments have been dug up and discussed, especially by the Hon. Mr. Stanley of Penrhos. Pen Caer Gybi is Roman. The island was devastated by the Danes (Dub Gint or black nations, gentes), especially in A.D. 853.
See Edw. Breese, Kalendar of Gwynedd (Venedocia), on Anglesey, Carnarvon and Merioneth (London, 1873); and The History of Powys Fadog.
ANGLESITE, a mineral consisting of lead sulphate, PbSO_{4}, crystallizing in the orthorhombic system, and isomorphous with barytes and celestite. It was first recognized as a mineral species by Dr. Withering in 1783, who discovered it in the Parys copper-mine in Anglesey; the name anglesite, from this locality, was given by F.S. Beudant in 1832. The crystals from Anglesey, which were formerly found abundantly on a matrix of dull limonite, are small in size and simple in form, being usually bounded by four faces of a prism and four faces of a dome; they are brownish-yellow in colour owing to a stain of limonite. Crystals from some other localities, notably from Monteponi in Sardinia, are transparent and colourless, possessed