TRIASSIC SYSTEM. 453 TRIBONIANUS. of a series of sandstones and shales extending more or less unbrokenly from the Connecticut Valley to South Can-olina. The rocks were de- posited in shallow water along the continental shores. The Newark rocks are in many places faulted and intruded by igneous rocks, the erup- tions having in some cases occurred while the deposition of sediment was still going on, be- ing thus in the nature of submarine outbursts. The Palisades of the Hudson River and the East Rock at New Haven, Conn., are formed of dia- base erupted during the Triassic period. Some doubt exists as to whether the Triassic rocks of the -tlantic border were one continuous belt or whether they were deposited in separated trouglis. In the interior of the continent along the Rocky ilountains there are extensive beds of red sandstone which were deposited in an in- land sea, but whether they belong to the Triassic or Jura-Trias is unsettled. On the Pacific Coast the Triassic rocks have a maximum thickness of nearly 5000 feet. Triassie rocks are known in Central and South America, Europe, Asia, and Australasia. The plant life of the Triassic included ferns, cycads, conifers, and gigantic representatives of the Equiseta or horsetails. The accumulated re- mains of these plants contributed to the for- mation of important coal seams. Among the vertebrates fishes were fairly abundant, the domi- nant type being ganoids; but the most character- istic class was the Amphibia, which attained its greatest development in this period. Of reptiles the ichthyosaurs, plesiosaurs, dinosaurs, croco- diles, and turtles were present, while the earliest representatives of the Mammalia came into ex- istence. The Triassic beds of the Atlantic border yield great quantities of sandstone (brownstone) for building, which has been quarried chiefly in the Connecticut Valley and New Jersey. De- posits of coal are found in the Triassic of Vir- ginia and North Carolina and in parts of Europe, but they are of minor importance compared with the great coal measures of the Carboniferous age. Bibliography. Kiimmel, "The Newark Rocks of New Jersey and New York," Journal of Geol- ogy, vii., pp. 23-52 ; Shaler and Woodworth, "Geology of the Richmond Basin, Virginia," yinFtcenth Annual Report of United States Geo- logical Surveij, part ii., p. 325; Russell. "The Newark System," Bulletin So, United States Geo- logical Siirrei/ ; Darton, "The Relations of the Traps of the Newark System in the New Jersey Region," Bulletin 61, United States Geological Survey : Davis, "The Triassic Formation of Con- necticut," ISIh Annual Report, United States Geological Surrey, part ii., p. 9; Hopkins, "The Brownstones of Pennsylvania," Bulletin Issued by Pcnnsylrania State College. See Geologt ; PALEOXTOLOGy ; etc. TRIBE (Lat. trihus, tribe; possibly con- nected with trahs. beam, Oscan triihom, Lith. iroha, building, OWelsh, OBret. ireh. habitation, subdivision of the people, Goth, paiirp. field, OHG. dorf, Ger. Dorf. Eng. thorp, village, or perhaps rather with Lat. tres, three, cf. Gk. Tpi<t)vi/c, tripliyes, Skt. tribhu, threefold, in al- lusion to the three legendary tribes of early Rome ; hardly connected with Gk. dr/jii) f rof , atrygetos, unfruitful, or with OChurch Slav. tri'igii, market-place). In general, an inter- related group, as a group of individuals defined on the basis of relationsliip; specifically, a con- sanguineal group of mankind. In savagery the social organization rests on the basis of kinship traced in the female or maternal line. Usually the family comprises the mother with her chil- dren. The role of the husljand and father is often that of a perpetual guest possessing little if any right over property or person ; while the several families of sisters "(i.e. daughters of the same mother) form a clan of which the mother or elderwoman is the lawgiver and her eldest brother the executive or chief. Commonly sev- eral such clans coexist and are united on the basis of real or assumed sisterhood of t!ie elder- women or on some other basis connected in some way with kinship; and the union constitutes a tribe in the specific sense of the term. Ordi- narily the tribe is perpetuated by marital regu- lations; mating is usually proscribed within the clan, which therebj' becomes exoganious, and prescribed within the tribe, which is therebj- ren- dered endogamous, and in more primitive so- cieties, such as that of the Australian natives and that of certain American aborigines, the laws are complex and restrict intermarriage to certain elans and even to a certain order within these clans. While the elderwomen remain law- givers in the tribe as in the clan, the larger or- ganization requires enlarged executive powers, which are usually vested in elder brothers of the matrons, so that the control is measurably or wholly avuncular. In a still fvirther enlargement of the group by multiplication of families the chiefs assume added prerogatives, and their power may rise above the kinship bonds and may even become hereditary, so that a reigning clan may be established. In the somewhat more advanced culture commonlv called barbarism the family and tribal organization undergo a change; paternity is recognized and kinship is traced in the male lines; and commonly the father assumes control of property and person, exercising author- ity not onl.v over his children, but over his wife or wives. This stage is that of patriarchy with its concomitants of enslavement and polygamy. In the patriarchal condition the group of closely related families forms a gens, while the less closely related gentes are usually organized in a tribe under a common chieftaincy. The organiza- tion is perpetuated partly by means of marital customs and partlv bv means of property regula- tions, while the ehiefship may be determined in various ways: yet the fundamental idea of the social organization or law remains that of kin- ship or consanguinity, either real or assumed. The chief function of the tribe is military, while that of the clan is juristic. The social organiza- tion on this basis is conveniently styled tribal societ.v, in contradistinction from the national society found among peoples organized on a territorial basis. Consult: Morgan, Ancient So- ciety (New York, 1877) ; Maine, Ancient Law. TRI'BONIA'NUS. A distinguished Roman jurist of the sixth century a.d. He was of Mace- donian parentage, but was born at Side, in Pam- phylia. He held, under the Emperor Justinian ( q.v. ) . the offices of quaestor, master of the Im- perial household, and consul. But he is famous chiefly through his labors in connection with the
