Mouth ulcers: Symptoms, treatment and prevention. Mouth ulcers are sores that appear in the mouth, often on the inside of the cheeks. Mouth ulcers, also known as apthous ulcers, can be painful when eating, drinking or brushing teeth.
Fossils are generally found in sedimentary rock. This occurs because the remains of plants and animals tend to accumulate with the inorganic debris that form such rock. In rare instances, fossils can form in igneous rock, as when volcanic ash or lava congeals around a leaf or insect wing, or fills a footprint.xposed rock is the collector's fruitful ground. Many interesting minerals and fossils can be found on weathered slopes, riverbanks, and cliff faces. Human-made excavations such as road cuts and construction or quarry sites can be excellent sites for mineral hunting.
The majority of fossils are found in clastic sedimentary rocks such as shale and sandstone. This type of rock is formed from mechanical weathering debris. Fossils are also found in limestone. Besides sedimentary rocks, fossils are also preserved in amber, which is formed from tree sap or resin. Usually, insects are the unfortunate organisms that get trapped and preserved in amber. Tar pits are another preservation medium for some animals.