### fossil:

Ammonite
* Most ammonites are more or less spiral, and some indeed resemble ram's horns
  - smooth-shelled, but some have ridges, knobs, horns, etc
  - have coiled shells
* are a dominant group
  - amongst the most abundant and well known of fossils
  - extinct relatives of modern cephalopods
  - flat spiral fossil shells of extinct cephalopods, from the the Mesozoic age
  - nautilus-like shells frequently found in fossil formations
  - relatives of squid, octopus and the chambered nautilus
* are some of the best known and most found invertebrate fossils in Cretaceous period rock
  - most fascinating fossils to be found and are incredibly diverse
  - the fossilized remains of ancient sea creatures
* are very common fossils in Jurassic rocks
  - popular with fossil collectors
* build their shells using two types, or isotopes, of oxygen atoms.
* evolve from nautiloids and become one of the dominant invertebrate forms.
* feed near the surface.
* look like snails but they are related to squids.
* recover from near extinction and become important guide fossils.
* seem to be different, with a hatching size much more like that of the coleoids.
* vary considerably in size.

Ammonite fossil
* are found on every continent.
* show the shape of the creature.

Ammonoid
* Some ammonoids swam in the sea, while others lived on the seafloor.
* differ from the nautiloids in some aspects.
* represent almost the totality of the nektonic macrofauna.

Body fossil
* are common in many places, but on the Earth as a whole they are fairly rare
  - fossilized hard skeletal parts, such as bones, teeth, and shells
* preserve some part of the organism either unaltered or altered by preservation.

Graptolite fossil
* are commonest in the black shales.
+ Hemichordata, Graptolites
  * The name graptolite comes from the Greek 'graptos', meaning 'written', and 'lithos', meaning 'rock'. Many graptolite fossils resemble hieroglyphs written on the rock. More recent work places them near the 'pterobranchs', possibly within.

Invertebrate fossil
* Some invertebrate fossils come from remains of the animals.
* are abundant, with remnants of snails and insects being common.

Mammoth fossil
* finds around the world gave rise to mythological explanations of their own.
* show a big change in tusk size over a long time period.

### fossil:

Microfossil
* are common in rocks from the Hadean
  - extremely important tools in biostratigraphy and paleoceanography
  - fossils of one-celled organisms which are rather tricky to interpret
* are fossils that are too small to be seen without a microscope
  - to be studied without the aid of a microscope
  - informative and abundant, occurring in many kinds of sediment
  - tiny fossils, either plants or animals, which can be seen only with a microscope
  - tiny, but recognizable, bits of plant or animal matter
* are useful for biostratigraphy or correlating sedimentary rocks
  - paleoenvironmental interpretation
  - very important in understanding the Precambrian fossil record
  - vital to oil exploration
* can provide important information about the ecology in the past
  - tell alot about past quakes
* tell scientists what organisms lived in the ocean in the past.
+ Micropaleontology: Fossils :: Paleontology
  * Microfossils are fossils generally not larger than four millimeters, and commonly smaller than one millimeter. A microscope is used to study them. Every kingdom of organisms is represented in the microfossil record. Microfossils can provide important information about the ecology in the past.

### fossil | microfossil:

Calcareous microfossil
* are sporadic, rarer downward, and moderately to poorly preserved.
* show evidence of reworking.

Siliceous microfossil
* are rare or absent in much of the core
  - relatively abundant, well preserved, and show no evidence of reworking
* disappear at even shallower burial depths in all holes.