58 DEVONIAN DEVONPOET are divided into Onondaga and corniferous limestone. Tins latter, from which the period take- it- name, is called corniferous because it contains macs of hornstone or imperfect flint. Tin- plants of this period are seaweeds and protophytcs, the cauda galli being among the former. The upper Helderberg epoch is the coral reef period of the palaeozoic ages, abound- ing in corals, some of which are found standing in tin- position in which they grew, but they are j_ r eiu rally more or less comminuted. This forma- tion attains in some places a thickness of 350 ft. Thecornifcrous period is especially remarkable for containing the earliest discovered remains of fishes, the first development of vertebrate animals. The oldest development of them has been found in the United States, in the Scho- harie grit. The Devonian formation contains two of the great divisions of fishes, the sala- chians or sharks, and the ganoids, of which the gar-pike and sturgeon are representatives. The Marcellus shale of the Hamilton period is a soft argillaceous rock, containing sufficient traces of coal to afford a flame when placed in a fire. The Hamilton beds contain shale and flagging stone, and are overlaid by the black Genesee shale. The Hamilton beds are re- markable for containing numerous ripple marks, and for having the strata intersected by regu- lar joints; fine examples of which are found near Cayuga lake, N. Y. These beds contain fine fossils of gasteropods, cephalopods, and trilobites. The Hamilton formation extends across New York from Lake Erie east, having its greatest thickness, about 1,200ft., east of the centre. It extends into Michigan, Illinois, and Iowa, in thinner strata. The rocks of the Portage epoch of the Chemung period have a thickness of 1,000 ft. on the Genesee river, and of 1,400 ft. near Lake Erie, but are not found in eastern New York. The Chemung group extends over the southern tier of coun- ties in New York, attaining in places a thick- ness of 1,500 ft. It abounds in organic re-
- >oth vegetable and animal, containing,
besides the cauda galli seaweed, numerous land
- md many species of crinoids, brachio-
pods, conchifers, bellerophons, and goniatites. The last period of the Devonian formation, the Cat-kill, i- composed mainly of shales and sand-ton,--, the latter predominating, passing into conglomerates particularly in the upper formation-. There are ripple marks and other ave action. The vestiges of animal r than in the earlier periods, and widely differ from them in character. No < rinoid-. l.raehiopods, or trilobites have ind. There are a feu concliifers and f ti-hea, some of which were of '.'-, the tins hein^a foot in length. The J.eds. however, have not U-eii fully explored. The land plant- are of much the same charac- ter with thus.- of the Chemung period. A frond of ,, n ,. ,,f the charaeteri-tic ferns, found at M..ntroM-, 1'a., Was IM ,, n . t ], an ft f Qot - n breadth. The Catskill formation is thin in the western part of New York, but along the Hudson river, in the Catskill mountains, it at- tains a thickness of 2,000 or 3,000 ft. It passes beneath the coal formation in Pennsylvania and Virginia, attaining in the Appalachian re- gion a thickness of 5,000 or 6,000 ft. The Devonian rocks appear at the surface in most parts of all the continents ; in Great Britain they appear in Wales, Herefordshire, Devon- shire, and Cornwall, and are also found in Ire- land and the Isle of Man ; but they are most developed in the United States. DEVONPORT, a parliamentary and municipal borough and naval arsenal in Devonshire, England, on the South of Devon railway, and on the Tamar, where that river makes a bold sweep toward the east and widens into the fine estuary called the Hamoaze, just before its entrance into Plymouth sound, 190 m. S. W. of London, and 1^ in. W. of Plymouth; pop. of parliamentary borough in 1871, 64,684. Its Guildhall, Public Library, and Column to commemorate the Renaming of the Town. harbor, one of several remarkable natural havens opening into the sound, is 4 m. long, % m. wide, from 15 to 20 fathoms deep, per- fectly safe, and capable of sheltering the whole British navy at once ; but it is difficult of en- trance. The town is bounded S. and W. by the river, and E. by a creek which separates it from Stonehouse, contiguous to Plymouth. With these two places it is so closely con- nected that the three may almost be said to form a single city, and it was not till 1824 that Devonport acquired separate municipal privileges, and changed its old name of Ply- mouth Dock for its present one. Among its schools are a naval and military free school, and an institution in which 100 girls are edu- cated and clothed. The town has a public library, orphan asylums, and a theatre. Water is brought from Dartmoor, in a winding con-
