The Romans used mainly wool for their clothing. Sheep grazing was widespread in Italy and wool was easy to produce and therefore affordable. Cotton and linen were imported from Egypt and were more difficult to produce and more expensive. Only the rich could afford them as well as silk from China. The very early Romans lived in wattle and daub huts. Stone foundations with holes in them to insert wooden strips called wattle to support the walls were made. The wattle was daubed with sticky materials. This was a combination of wet soil, clay, sand, dried animal dung and straw. The roof was probably thatched. Later the Romans used stone. The used the local volcanic rock which is called tuff. Later still, they also used volcanic rocks from nearby areas, peperino and travertine. Marble, granite and porphyry from Italy and elsewhere in the Mediterranean were also used. The Romans also developed concrete which was a mix of quick lime, pozzolana (a volcanic rock found in Pozzuoli, which is now a suburb of Naples) and an aggregate of pumice. For food the Romans used the local fruit and vegetables. These did not include oranges and water melons which were introduced later and tomatoes, which come from America. Lemons were introduced in the 1st century AD, but were not widely cultivated; peaches were introduced in the 1st century AD and melons towards the end of the empire. Apricots and Almonds were popular. The Romans did not eat much meat from farm animals, except for pigs, chicken and geese. Beef, especially, was not eaten because it did not last long in the heat and because cows were used to make dairy products. They ate game (pheasants, pigeons, duck partridges, doves, thrushes, fig-peckers, and, for the rich, peacocks, ostriches and cranes) and other wild animals (boar, venison, wild goat, boar) and grazing animals: lamb and mutton . Fish was expensive and only eaten occasionally. The rich had fishponds in their garden.