Lithology sense of displacement across the zone. In igneous rocks, small-scale structures are mostly observed in lavas such as pahoehoe versus ʻAʻā basaltic flows, and pillows showing eruption within a body of water or beneath ice. Unconsolidated surficial materials may also be given a lithology. This is defined by grain size and composition, and is often attached to an interpretation of how the unit formed. Surficial lithologies can be given to lacustrine, coastal, fluvial, aeolian, glacial, and recent volcanic deposits, among others. Examples of surficial lithology classifications used by the US Geological Survey are, "Glacial Till, Loamy", "Saline Lake Sediment", and
History of the petroleum industry in Canada (natural gas) hydrogen sulphide out of a gas stream is called "sweetening" the gas. The Union Natural Gas Company of Canada (now Union Gas Ltd.) of Chatham-Kent, Ontario built Canada's first Koppers process sweetening plant in 1924 at Port Alma, Ontario, to scrub Tillbury gas. Hydrogen sulphide is a dangerous substance which at low concentrations has an obnoxious rotten egg smell. This odour annoyed Union's customers and prompted it to build the Port Alma plant. It removed hydrogen sulphide by exposing the sour gas to dissolved soda ash. Although previously used on coal gas, the application at the Port Alma plant was