Compared with some other periods, the Cambrian was free from extensive volcanic disturbances, but in Wales and in Brittany the earlier portions of this period were marked by voluminous outpourings; a condition that was feebly reflected in central and southern Europe.
No definite conclusions can be drawn from the fossils as to the climatic peculiarities of the earth in Cambrian times. The red rocks may in some cases suggest desert conditions; and there is good reason to suppose that in what are now Norway and China a glacial cold prevailed early in the period.
Considerable variations occur in the thickness of Cambrian deposits, which may generally be explained by the greater rapidity of deposition in some areas than in others. Nothing could be more striking than the difference between the thicknesses in western and eastern Europe; in Brittany the deposits are over 24,000 ft. thick, in Wales at least 12,000 ft., in western England they are only 3000 ft., and in northern Scotland 2000 ft., while no farther east than Scandinavia the complete Cambrian succession is only about 400 ft. thick. Again, in North America, the greatest thicknesses are found along the mountainous regions on the west and on the east—reaching 12,000 ft. in the latter and probably nearly 40,000 ft. in the former (in British Columbia)—while over the interior of the continent it is seldom more than 1000 ft. thick.
Any attempt to picture the geographical conditions of the Cambrian period must of necessity be very imperfect. It was pointed out by Barrande that early in Palaeozoic Europe there appeared two marine provinces—a northern one extending from Russia to the British Isles through Scandinavia and northern Germany, and a southern one comprising France, Bohemia, the Iberian peninsula and Sardinia. It is assumed that some kind of land barrier separated these two provinces. Further, there is a marked likeness between the Cambrian of western Europe and eastern America; many fossils of this period are common to Britain, Sweden and eastern Canada; therefore it is likely that a north Atlantic basin existed. Prof. Kayser suggests that there was also a Pacific basin more extensive than at present; this is borne out by the similarity between the Cambrian faunas of China, Siberia and Argentina. The same author postulates an Arctic continent, bordering upon northern Europe, Greenland and North America; an African-Brazilian continent across the present south Atlantic, and a marine communication between Australia and India, where the faunas have much in common.
References.—The literature devoted to the Cambrian period is very voluminous, important contributions having been made by A. Sedgwick, Sir R.I. Murchison, H. Hicks, C. Lapworth, T. Groom, J.W. Salter, J.E. Marr, C.D. Walcott, G.F. Matthew, E. Emmons, E. Billings, J. Barrande, F. Schmidt, W.C. Brögger, S.A. Tullberg, S.L. Torngrist, G. Linnarsson and many others. A good general account of the period will be found in Sir A. Geikie’s Text-Book of Geology, vol. ii. 4th ed. 1903 (with references), and from an American point of view, in T.C. Chamberlin and R.D. Salisbury’s Geology, vol. ii., 1906 (references to American sources). See also J.E. Marr, The Classification of the Cambrian and Silurian Rocks, 1883 (with bibliography up to the year of publication); A. Geikie Q.J. Geol. Sac., 1891, xlvii., Ann. address, p. 90; F. Frech, “Die geographische Verbreitung und Entwickelung des Cambrium,” Compte Rendu. Congrès Géol. Internal. 1897, St-Pétersbourg (1899); Geological Literature added to the Geological Society’s Library, published annually since 1893.
(J. A. H.)
CAMBRIC, a word derived from Kameryk or Kamerijk, the Flemish name of Cambrai, a town in the department of Nord, France, where the cloth of this name is said to have been first made. It was originally made of fine linen. There is a record of a privy purse expenditure in 1530 for cambric for Henry VIII.’s shirts. Cambric has been used for many years in the manufacture of handkerchiefs, collars, cuffs, and for fine underclothing; also for the best shrouds, and for fine baby linen. The yarns for this cloth are of very fine quality, and the number of threads and picks often reaches and sometimes exceeds 120 per inch. Embroidery cambric is a fine linen used for embroidery. Batiste, said to be called after Baptiste, a linen-weaver of Cambrai, is a kind of cambric frequently dyed or printed. All these fabrics are largely copied in cheaper materials, mixtures of tow and cotton, and in many cases cotton alone, taking the place of the original flax line yarns.
CAMBRIDGE, EARLS AND DUKES OF. Under the Norman and early Plantagenet kings of England the earldom of Cambridge was united with that of Huntingdon, which was held among others by David I., king of Scotland, as the husband of earl Waltheof’s daughter, Matilda. As a separate dignity the earldom dates from about 1340, when William V., count (afterwards duke) of Juliers, was created earl of Cambridge by King Edward III.; and in 1362 (the year after William’s death) Edward created his own son, Edmund of Langley, earl of Cambridge, the title being afterwards merged in that of duke of York, which was bestowed upon Edmund in 1385. Edmund’s elder son, Edward, earl of Rutland, who succeeded his father as duke of York and earl of Cambridge in 1402, appears to have resigned the latter dignity in or before 1414, as in this year his younger brother, Richard, was made earl of Cambridge. In the following year Richard was executed for plotting against King Henry V., and his title was forfeited, but it was restored to his son, Richard, who in 1415 became duke of York in succession to his uncle Edward. Subsidiary to the dukedom of York the title was held by Richard, and after his death in 1460 by his son Edward, afterwards King Edward IV., becoming extinct on the fall of the Yorkist dynasty.