Chondrichthyes: Fish with a skeleton composed of cartilage rather
than bone; sharks are an example.
Cretaceous: The time period between 146 to 65 million years ago when
dinosaurs were prevelant.
Cusp: A point or bump on the crown of a tooth.
Direct Evidence: Evidence that can be observed directly with our senses.
Element: A specific fossil structure. For example, teeth, scales, vertebrae, etc. are each different elements.
Fossil: Any evidence of past life, including the remains of hard parts of organisms, molds, and casts.
Gar: A predatory fish that includes several freshwater species of the genus Lepisoteus. Its body is covered with very hard diamond-shaped scales and it has a beak armed with large teeth. Gars have existed since the late Cretaceous (100 million years ago) and are still alive today.
Indirect Evidence: Evidence based upon logical reasoning or inference.
K-T Boundary: The time between the late Cretaceous and Early
Tertiary periods when a mass extinction took place.
Matrix: The material surrounding fossils; sandstone, sedimentary rock, etc.
Multi-tuberculate: A member of a group of mammals that first appeared in the late
Jurassic (163-144 million years ago) and went extinct in the early
Oligocene (36-30 million years ago). They are named for the many small
cusps (tubercles) on their teeth.
Osteichythyes: Fish with skeletons composed of bone. Goldfish and gar are examples.
Outcrop: Exposed hillside. Outcrops are great places to look for fossils that may have been exposed by geologic events and erosion.
Serrations: Notches that are part of a sawlike edge (like a serrated knife). Serrations are diagnostic features of carnivorous dinosaur teeth.
Sieve: A screening box or sorting box used to separate certain sized fossils.
Sorting: A technique used to separate fossils. Includes rough sorting and sorting by element. Rough sorting is the process of separating fossils from matrix. Sorting by element is the process of separating the fossils into groups (i.e. by teeth, vertebrae, scales, etc.) .
Striations: Shallow grooves or thin parallel lines.
Tertiary: Time period lasting from 65 to 1.8 million years ago, after
the mass extinction.
Theropod: A group of bipedal carnivorous dinosaurs.
Topographical Map: A map that contains a graphical representation of the physical features of a particular area. "Topo" lines on a map represent incremental changes in altitude from one area to another.
UCMP: University of California Museum of Paleontology.
Washing and Screening: A technique used
to separate fossils using a series of different sized screened boxes and
water.