Examples of index fossils. Index fossils (also known as guide fossils, indicator fossils or zone fossils) are fossils used to define and identify geologic periods (or faunal stages).
Methyl cellulose. Methyl cellulose (or methylcellulose) is a chemical compound derived from cellulose. It is a hydrophilic white powder in pure form and dissolves in cold (but not in hot) water, forming a clear viscous solution or gel.
Damico...you're correct that DCM is soluble in water, but for practical purposes it is not soluble in water. DCM's solubility in water is quite low and is capable of being used in separations from aqueous solution. It is also true that oil is soluble in water, but the solubility is very very low. Everything is soluble to an extent. I would never pour oil into drinking water, separate and then drink the water. Some oil will remain, but for purposes of separation we consider DCM to be insoluble.