Trenches cut by the plough are called furrows. The Upanishad also states that Sita emerged while furrowing, at the edge of the plough. Cows were prized for the milk; bulls as plough and draft animals. Examples include the Big Dipper/Plough and the Northern Cross. It had land for 1 plough, of meadow. These include the "two-teeth" plough and an early sickle. Many manufacturers produce a plough-type anchor, so-named after its resemblance to an agricultural plough. If Joey won't plough, Ned gets the horse. The frog is in turn fastened to the plough frame. The heavy wheeled plough was introduced in the late 10th century. Columella quotes Vergil's comment that loose soil is "what we rival when we plough". The first part was a coulter at the bottom of the plough. It can be also fitted with a mine plough. This was accompanied by larger fields, known variously as carucates, ploughlands, and plough gates. Joseph Foljambe's "Rotherham plough" of 1730 was the first commercially successful iron plough.