alluvial: Clay, sand, gravel, or rock material deposited by running water.
anthracite coal: Hard, lustrous natu- ral fuel, longer-burning and hotter than bituminous coal because it con- tains less volatile matter.
anvil stone: A stone with a flat or cupped surface on which seeds or nuts are cracked or ground with a hand-held smooth stone.
argillite: A compact rock metamor- phosed from clay cemented by silica.
artifact: Object made or adapted by man.
atlatl: Flat or rounded shaft with a hook in one end to receive the hol- lowed end of a projectile shaft, en- abling the holder to propel the weapon with great force.
balk: Unexcavated area between exca- vated grid units at a site, left to pro- vide a stratigraphic section.
biface: Worked on both sides to fash- ion an object, here of stone.
bituminous coal: A soft coal that yields less heat and burns more quickly than anthracite coal.
bola stone: Two or more round stones tied together and thrown at an animal so as to entangle it and bring it down.
carbon 14 (radiocarbon dating): Iso- tope of carbon rendered radioactive in the high atmosphere, which, falling to earth, is found in the remains of or- ganic substances. Because its half-life is known, C can be used to date a substance by measuring its dimin- ished radioactivity.
celt: Stone implement with a ground edge, usually hafted in a wood shaft like a mattock or chisel, and used prin- cipally to trim or hollow out wooden objects, here by the Amerindians.
chalcedony: Translucent, colored quartz stone with the properties of flint—e.g., conchoidal (shell-like) fracture.
chert: A flint-like rock characterized by conchoidal fracture, rendering it useful in making artifacts by flaking, like the chalcedony of which it is mainly composed.
city datum: In Philadelphia, an ele- vation reference 2.25 feet above mean high water mark at the foot of Chest- nut Street, with reference to the Dela- ware River.
cross-mend: Sherds from different strata or site locations matched to in- dicate portions of a single vessel.
dolomite: A limestone or marble rich in magnesium carbonate.
ecology: The pattern of relationships between organisms and their environment.
ethnology: The analytical and com- parative study of historic human groups.
fall line: The line joining the rapids on rivers falling to the sea and marking the limit of navigability for each river.
feature: Soil disturbance or man- made (or adapted) construction.
flint: Hard siliceous stone, occurring in nodules in limestone formations, that is characterized by a conchoidal fracture ideal for making aboriginal flaked tools and gunflints, and for producing sparks when struck by iron or steel.
gabbro: A granular igneous rock corn- posed of calcium carbonate, ferrous magnesium, and other minerals.
gneiss (Baltimore gneiss): Foliated granitic rock.
grade: An original surface before deposition or erosion has changed it. In archaeology, a historical surface of reference.
granite: A hard igneous rock with a crystalline texture used for building.
grave offering: Artifacts buried with the dead.
grid system: Method of excavation in which features, artifacts, and exca- vation areas are related to the coordi- nates of the grid.
Holocene: Recent. Generally, after the glacial age.
hominid: Any of a family of primates comprising the ancestors of modern man.
Homo sapiens: Species name of mod- ern man: Homo for the genus, sapiens a specific epithet meaning wise— sometimes doubled to sapiens sapiens.
indenture: A contract binding one person to work for another for a given period of time in exchange for keep and training.
jasper: An opaque, compact, variety of stone stained with various colors (red, green, yellow, etc.) and having the conchoidal fracture characteristic of flint, making it useful for flaked arti- facts.
limestone: A water-deposited rock formation consisting of the calcium carbonate of shells and corals; may be cut for building stone or crushed and burned to make lime for mortar.
lithic: Stone, as applied here to mate- rials used for making artifacts.
longhouse: Long communal dwelling of the Late Woodland Amerindians extending into the time of contact, notably among the Iroquois.
longitudinal profile: A section through the longest axis of an archaeological feature.
matrilineal: Tracing of descent through the mother's line.
mean ceramic date: The midpoint be- tween the earliest and latest ceramic dates at a site, based on the known