6,000. Apart from farming, Gabriola experienced industrial development in the 20th century. A brickyard produced a day in the early part of the century, and they were sent principally to Victoria and Vancouver. The brickyard ceased functioning in the 1950s. In the 1890s and early twentieth century, sandstone blocks were cut from a quarry near Descanso Bay and shipped for architectural use in public buildings in Vancouver and Victoria. In the early- to mid-1930s, millstones were cut from the sandstone and sent to towns along the west coast and as far away as Finland for use in the pulp and paper industry. A small diatomaceous earth industry also flourished in the 1930s. After World War II, the shipyard at Silva Bay became the major employer on the island until the 1970s. Geography Gabriola, part of the Regional District of Nanaimo, is the most northerly of the Southern Gulf Islands in the Strait of Georgia between mainland BC to the east and Vancouver Island to the west. The Gulf Islands are an archipelago consisting of hundreds of islands of various sizes stretching from the San Juan Islands in the United States to the Northern Gulf Islands, north of Gabriola. The biggest of the Southern Gulf Islands are Gabriola Island, Galiano Island, Kuper Island, North and South Pender Island, Saltspring Island, Saturna Island, Thetis Island, and Valdes Island. The Southern Gulf Islands consist mainly of former seabed sediments crumpled and gradually thrust upward by tectonic plate movement between ago. Subsequent periods of glaciation scraped away topsoil and some of the bedrock. During the peak of the Fraser Glaciation, ago, Gabriola was covered with ice up to thick. Though melting glaciers left deposits of sand, gravel, and boulders, the main rocks exposed on Gabriola's surface are sandstone and shale. Differential erosion of relatively soft shales and relatively hard sandstones helped create cliffs, points, and bays along Gabriola's shoreline. Gabriola is about long by wide on average with a land area of . The topography varies from flat sandy beaches at sea level to forested hills rising to on Stoney Ridge in the centre of the island. Gabriola lies about east of Nanaimo, the second largest city on Vancouver Island, to which it is linked by BC Ferries. The ferry, which takes 20 minutes for the crossing, runs almost hourly from 6:15 a.m, starting at the Gabriola side, to about 11:00 p.m. ,from Nanaimo,