GEOLOGY

Detailed explanation-1: -Fossils are typically found in sedimentary rocks and occasionally some fine-grained, low-grade metamorphic rocks. Sometimes the fossils have been removed, leaving moulds in the surrounding rock, or the moulds may have later been filled by other materials, forming casts of the original fossils.

Detailed explanation-2: -Fossils are mostly found where sedimentary rocks of the right age – which for dinosaurs is the Mesozoic – are exposed. The best places are river valleys, cliffs and hillsides, and human-made exposures such as quarries and road cuttings.

Detailed explanation-3: -Weathering and erosion from wind, rain, ice, heat and rivers break rocks apart and wash the fragments away. David says, ‘It can take millions of years, but gradually fossils become exposed at the surface where we can find them.

Detailed explanation-4: -Fossilization on land is very uncommon, however, because most areas of the land are being eroded. Unless there is deposition, fossils cannot be preserved. Deposition on land is common only in river valleys. Fossils are fairly common in sediments deposited on river floodplains.