Columbia Encyclopedia

(Encyclopedia) stromatolite, layered structures produced by the binding together of sediments by a thin layer of cyanobacteria. The layers, which are deposited very slowly, gradually produce rounded or hummocklike f...

(Encyclopedia) La Brea lə brāˈə [key], area, S Calif., formerly in Rancho La Brea. The La Brea asphalt pits, which yielded prehistoric animal and plant remains, are in Hancock Park, Los Angeles. The first fossil...

(Encyclopedia) Olduvai Gorge ōlˈdəwāˌ, –vāˌ [key], a feature of the E African Rift Valley in Tanzania. Erosional processes have exposed geological strata in the gorge dating to the lower Pleistocene epoch, ...

(Encyclopedia) Dryopithecus drīˌōpəthēˈkəs, –pĭthˈəkəs [key], an extinct group of apes. Fossils about 20 million years old have been found in Africa, Asia, and Europe. Dryopithecus had a semierect postu...

(Encyclopedia) Turkana, Lake, c.2,500 sq mi (6,475 sq km), NW Kenya and SW Ethiopia, E Africa, in the Great Rift Valley; alt. 1,230 ft (375 m). Surrounded by desolate, volcanic mountains, the 170-mi-long (274-km) al...

(Encyclopedia) Lahontan, Lake ləhŏnˈtən [key], extinct lake of W Nev. and NE Calif. It was formed by heavy precipitation caused by the Pleistocene glaciers and with Lake Bonneville (see under Bonneville Salt Fla...

(Encyclopedia) Devonian period dĭvōˈnēən [key], fourth period of the Paleozoic era of geologic time between 408 and 360 million years ago (see Geologic Timescale, tablegeologic timescale, table). It was named (...

(Encyclopedia) Osborn, Henry Fairfield, 1857–1935, American paleontologist and geologist, b. Fairfield, Conn. He was professor of comparative anatomy (1883–90) at Princeton, and professor of biology (1891–96) ...

(Encyclopedia) Brongniart, Adolphe Théodore ädôlfˈ tāōdôrˈ brôNyärˈ [key], 1801–76, French botanist; son of Alexandre Brongniart. He was a pioneer in the study of plant morphology and physiology and was...

(Encyclopedia) Rhyniophyta rīˌnēŏfˈətə [key], division of plants known only from fossils, of which the genus Rhynia was perhaps the most important. These plants date from the Silurian and Devonian age. Relati...