assemblages

• Life assemblage is when organisms are preserved as they lived. There is not transport of them after they died. There are a large number of species preserved. Range of individuals from juvenile to adults. Good quality of preservation and no alignment with current. 
• Death assemblages are when organisms are not preserved on situ. There may be erosion and sorting by size due to currents which may align with the current. 
• Fossils may be derived from older rocks and mixed with younger sediment. It would show some signs of abrasion and loss of detail, unless derived fossils are recognised then age of bed may be confused.