Columbia Encyclopedia

(Encyclopedia) foraminiferan fərămˌənĭfˈərən [key], common name for members of the class Foraminifera, large, shelled ameboid protozoans belonging to the phylum Sarcodina. Most foraminiferan shells are calca...

(Encyclopedia)  CE5 geologic timescale, a chronological scale of earth's history used to measure the relative or absolute age of any part of geologic time. Of the numerous timescales, the most common is based on g...

(Encyclopedia) Archaeopteryx ärˌkēŏpˈtərĭks [key] [Gr.,=primitive wing], a 150 million-year-old fossil animal first discovered in 1860 in the late Jurassic limestone of Solnhofen, Bavaria, and described the f...

(Encyclopedia) Proconsul, extinct group of apes. Proconsul fossils have been discovered in E Africa. It had a mixture of ape and Old World monkey characteristics, and lived from 23 to 25 million years ago. ...

(Encyclopedia) period, unit of time on the geologic timescale. Periods are shorter than an era and longer than an epoch. Periods are of variable length, generally lasting tens of millions of years, with characterist...

(Encyclopedia) Cambrian period [Lat. Cambria=Wales], first period of the Paleozoic geologic era (see Geologic Timescale, tablegeologic timescale, table) extending from approximately 570 to 505 million years ago. It ...

(Encyclopedia) badlands, area of severe erosion, usually found in semiarid climates and characterized by countless gullies, steep ridges, and sparse vegetation. Badland topography is formed on poorly cemented sedime...

(Encyclopedia) Lepidodendron sĭjĭlârˈēə [key], two principal genera of an extinct group of primitive vascular trees. They dominated the forests of the early Carboniferous period until the ferns gained ascendan...

(Encyclopedia) Pitch Lake, pool of pitch (asphalt), c.114 acres (46 hectares), SW Trinidad island, Trinidad and Tobago, near La Brea. The lake is believed to be formed and supplied by the seepage of natural pitch, a...

(Encyclopedia) Oreopithecus ôrˌēōpĭthˈəkəs, –pĭthēˈkəs [key], extinct genus of apes whose fossils have been found in E Africa and Italy. It is best known through specimens preserved in coal deposits. I...