ARCH, JOSEPH, an English agriculturist, b. 1828. His parents were in humble circumstances, and he educated himself; at an early age he became an advocate of tem perance and a Methodist local preacher. He rebelled against the low price paid for farm-labor, and after much struggle and suffering became a leader in efforts to better the condition of laboring men. In 1872, the national agricultural laborers' union was formed, and A. became its president. In 1873, he visited Canada and the United States to study the condition and prospects of labor, and the question of emigration.
ARCHzE'AN, or Azote, PERIOD—from Hie Greek for beginning—commencing with the earliest formation of the earth's crust, is the period to which are assigned the oldest rocks on which those of late ages have been spread, and from which most of them have been made. The arelicean rocks, extending, round the globe, are in most places shut out from sight by the later formations, yet in vanous parts of both hemispheres, rising above the rest, they are exposed to view as surface rocks. In Europe they are visible in the n.w. of Scotland, in the iron regions of Norway and Sweden, in the n.w. and me. of Russia, down to the White sea, in the Ural mountains, and further s. in Podolia. In central Europe they appear in the midst of the more recent formations, protrude frequently in the Carpathian mountains and central crests of the Alps, and in Bavaria and Bohemia between the Danube and the Elbe. In North America they rise to the surface in a large district between the Arctic circle and the great lakes, in a tract s. of lake Superior and another in southern New York, in the Highlands, and in the central part of the Appalachian chain and Rocky mountains. In Canada, where they have been carefully studied, they are believed to be more than 30,000 ft. thick; in Europe their exact thick
ness can scarcely be conjectured, yet it must be many thousand feet. These rocks are chiefly crystalline, such as granite, syenite, gneiss, svenitic gneiss, mica-schist, horn blende schist, chlorite slate, and granular limestone. There are also some hard conglom erates, quartz rocks, and slates. They very often contain iron-bearing minerals, and immense beds of iron ore are found with them in northern New York—where they are from 100 to 200 ft. thick—New Jersey, Michigan, and south of lake Superior. Graphite also is found abundantly throughout the archwan rocks of Canada and the adjacent parts of the United States. In the archrean rocks indications of life are almost if not entirely wanting. For this reason the period is named also the azoic, lifeless. But in the lime stones of Canada a form has been discovered which is thought by eminent geologists to be a coral-like fossil made by protozoans of the class of rhizopods, the simplest kind of animal life. Its organic nature has not indeed been placed beyond doubt; still geologists think it probable that rhizopods existed in the waters before the close of the archrean period, and that the beds of limestone have been made up of their minute shells. The abundance of graphite found throughout the archrean rocks of Canada and the United States is also regarded as an indication that organic plants then existed, as it is known that in late times graphite has been formed out of such remains. For these reasons the name eozoie—the dawn of life—has been proposed for the later portion of the archrean period.