Isle of Portland in the context of "Portland, Maine"

A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to manage their safety risks and reduce their environmental impact.

The word quarry can also include the underground quarrying for stone, such as Bath stone.

Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone. It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, and then grinding the clinker with the addition of several percent (often around 5%) gypsum. Several types of Portland cement are available. The most common, historically called ordinary Portland cement (OPC), is grey, but white Portland cement is also available.

The cement was so named by Joseph Aspdin, who obtained a patent for it in 1824, because, once hardened, it resembled the fine, pale limestone known as Portland stone, quarried from the windswept cliffs of the Isle of Portland in Dorset. Portland stone was prized for centuries in British architecture and used in iconic structures such as St Paul's Cathedral and the British Museum.

Portland stone is a limestone geological formation (formally named the Portland Stone Formation) dating to the Tithonian age of the Late Jurassic that is quarried on the Isle of Portland in Dorset, England. The quarries are cut in beds of white-grey limestone separated by chert beds. It has been used extensively as a building stone throughout the British Isles, notably in major public buildings in London such as St Paul's Cathedral and Buckingham Palace. Portland stone is also exported to many countries, being used for example at the United Nations headquarters in New York City.

Portland (/ˈpɔːrtlənd/ PORT-lənd) is the most populous city in the U.S. state of Oregon. Located in the Pacific Northwest at the confluence of the Willamette and Columbia rivers, it is the 28th-most populous city in the United States, sixth most populous on the West Coast, and third most populous in the Pacific Northwest (after Seattle and Vancouver, British Columbia) with a population of 652,503 at the 2020 census. The Portland metropolitan area, with over 2.54 million residents, is the 26th-largest metropolitan area in the nation. Almost half of Oregon's population resides within the Portland metro area. It is the county seat of Multnomah County, Oregon's most populous county.

The Portland area was shaped by massive ice-age floods. It was inhabited by the Chinookan peoples. European American settlers arrived in the 1840s. Portland was named after Portland, Maine, following a coin toss, which was itself named after England's Isle of Portland. In the 19th century, Portland became a major port and lumber center and gained a reputation for saloons and crime. The 20th century saw population growth, World War II shipbuilding, Japanese-American internment, organized crime, and a hippie/counterculture movement. Since the 1990s, it has experienced growth in the technology sector and rising housing costs. It saw major George Floyd protests in 2020–2021.

A tied island or land-tied island is a landform consisting of an island that is connected to the mainland or another island only by a tombolo, which is an isthmus of beach materials connected to land at both ends. St Ninian's Isle in the Shetland Islands off the north coast of Scotland is an example: it was once an island but is now linked to the mainland.

Other examples include Maury Island, Washington in Puget Sound, Coronado, California, and Nahant, Massachusetts in the United States; Paraguana Peninsula in Venezuela; Barrenjoey, New South Wales and Wedge Island, Western Australia; Paratutae Island in New Zealand; the Argentario and Sestri Levante in Italy, Mount Hakodate in Japan, Howth Head in Ireland; Davaar Island, Campbeltown, Scotland; Chefoo island in Yantai, China; and Cheung Chau in Hong Kong.

Chesil Beach (also known as Chesil Bank) in Dorset, England, is one of three major shingle beach structures in Britain. Behind the beach is the Fleet, a shallow tidal lagoon.

The beach runs for a length of 29 kilometres (18 mi) from West Bay to the Isle of Portland and in places is up to 15 metres (50 ft) high and 200 metres (660 ft) wide. It is almost entirely made of stone shingle, and the typical size of stones reduces along the length of the beach. The beach is often identified as a tombolo, although research has revealed that it is in fact a barrier beach.