.V.' I 



OLDIIAMIA 



OLD RED SANDSTONE 



are tin- K.-.-um (1854-80), a school of science 

 and art (1805), ]>ul>lir baths (18A4). an inlirinary 

 il>70 77), mill the Alexandra Park of 72 acres 

 (1805). Olilliiini received its charter of incor|>ora- 

 tipn in 1849. It WOK enfranchised by tin- Reform 

 Bill of 1832, ami ret u run two inemU'rs, the parlia- 

 mentary borough (which extomlH into Ashton- 

 nnder-Lvne paii-h i covering 194, so,, in., the muni- 

 cipal only II. Pop. of the former ( 1881 ) 152.;.i:i; 

 of the latter (1801) 12,024; (1841) 42,595; (1881) 

 111.343; (1891) 130,403. 



Olilhailliil. a genus of fn ils of unknown 

 affinities met with in the Cambrian system. <>ld- 

 hamia assumes various form-, sometimes con-i-i 

 ing of nhort radiating branches or unihels, which 

 spring at regular intervals from a central thread- 

 like axis; at other times the branches radiate in 

 all direction* from a central point. Some pale- 

 ontologists have supposed the fo-.il to lie a Ser- 

 tularian zoophyte; other* have referred it to the 

 polyzoa; while' yet others think it may be a sea- 

 weed. Possibly it is not a fossil at all, but merely 

 an inorganic structure. 



Oldhaven Beds. See EOCENE SYSTEM. 



Oldmixon. JOHN (1673-1742), author of dull 



histories oi Kngland, Scotland, Ireland, and 



Aim-hen, and of works on logic and rhetoric, is 



known eliielly as one of the heroes of Pope's 



/</. 



Old Mortality. See PATERSON (ROBERT). 



Old Point Comfort, a village and watering- 

 place of Virginia, at the month of James River, on 

 Hampton Roads, is the site of Fortress Monroe. 



Old Red Sandstone and Devonian 

 S> -tcm. the name given to certain series of strata 

 that are intermediate in age between the Silurian 

 and Carboniferous systems. These, known respec- 

 tively as 'Old Red Sandstone' ami ' Devonian,' are 

 nowhere seen together, hut the one is believed to 

 lie the equivalent of the other. 



nl'l Ii'-il Smalltime. This series, which underlies 

 the Carboniferous system, was so called to distin- 

 gui-h it from another set of red sandstones which 

 rests upon the Carlnmiferoiis strata, and was for- 

 merly known as the New Ked Sandstone (see 

 PEIOHAN, and TIMASSIC). In the British Islands 

 tli<- ( ilil Red Sandstone i- routined to Scotland, 

 Wales, and Ireland. In Scotland it comprises two 

 groups of strata, the upper resting nnconformahly 

 on the lower. The lower group attains a great 

 tliiekness (20,000 feet as a maximum), and con- 

 -i-n of coarse red, gray, brown, and purplish and 

 sometimes yellowish sandstones, gray flagstones, 

 elavH, and shale-, coarse conglomerates, and local 

 lH-.is of limestone and cornstone. Associated with 

 these strata are interbedded lavas (porphyrites, 

 diabase, &c.) and lulls, which in some regions 

 (SidlawK, Orhils, Pent lands, Cheviots, Ayrshire, 

 reach several thousand feet in tliiekness. The 

 ;U of the Lower Old Red Sandstone consist 

 chiefly of fishes and crustaceans and liadly -preserved 

 plants, which are mostly lycojiodiaceoiis. In Lanark- 

 shire a thin lied of shale in the group has yielded 

 a few Upper Silurian fossils. The i</ii>er i/nnifi 

 comprises red sandstones, clays, conglomerates, 

 and breccias, the sandstones in some areas licing 

 gray, yellow, or white. Few fossils occur, and 

 these are chiefly the remains of ganoid fishes. In 

 Arran the group contains a linn-tone which has 

 yielded nifitine Carboniferous fos-ils. In some 

 placi-* this group pass-ex upwards conformably into 

 the lower mcmlier of the (arlu>niferous system. 



In Wales the Old Red Sandstone BMsan to 

 graduate downwards into the Upper Silurian, and 

 to lie likewise conformable with the overiyina 

 Carboniferous strata. In Ireland, as in Scotland^ 



there appears to lie an unconformity lictwecn the 

 upper and lower groups of the series, the former 

 rtffirinp; conformably upwards into the Carbonifer- 

 ous, and the latter ( ' I llcngarilf (Jrit* 1 ) graduating 

 downwards into the t'p]>er Silurian. 



In Scotland the Old Red Sandstone strata are 

 developed chiefly in the I/owlands, but here and 

 there they rise to considerable elevations. They 

 Hank the Palieozoic strata of the southern up- 

 lands and the Highlands, and are probably more or 

 less continuous underneath the overlying Carlion- 

 iferous strata throughout the whole breadth of 

 central Scotland. Other wide areas occur in the 

 lower basin of the Tweed, along the borders of the 

 Moray Firth, in Caithness, Orkney Islands, iVc. 

 In Wales the Old Red Sandstone is well developed 

 in the region watered by the Usk and the Wye. 

 In Ireland it is met with chiefly iu the west and 

 south-west. 



Devonian. In Devon and Cornwall we meet 

 with a very different series of strata occupying the 

 same stratigraphical position as the OKI Red Sand- 

 stone. The Devonian strata pass up conformably 

 into the Carboniferous system, but the base of the 

 series is not seen, up that the relation of the strata 

 to the Silurian is not known. The English 

 Devonian probably does not exceed 10,000 or 12,000 

 feet in thickness. It consists of three groups 

 (Lower, Middle, and Upper), the rocks being prin- 

 cipally gray ami brown slates, brown, yellow, 

 red, and purple sandstones, grits, conglomerates, 

 calcareous slates, and limestones. The calcareous 

 memliers of the series are generally well charged 

 with fossils of marine types, and are developed 

 chiefly in the middle group. 



Devonian rocks occupy wide areas at the surface 

 on the Continent. They appear in tlie north of 

 France, and extend from the Bonlonnais eastwards 

 through Belgium to Westphalia. In northern 

 Russia they extend over more than 7000 miles, and 

 crop up along the Hanks of the I' nils. Hut the 

 areas exposed to view probably bear but a small 

 proportion to those which lie buried underneath 

 later formations. In central Europe the strata 

 have the general aspect of the English Devonian, 

 and contain relics of the same marine fauna. In 

 Russia the strata are remarkable for showing niter- 

 nations of calcareous and arenaceous rocks- the 

 former of which contain an assemblage of fossils of 

 a Devonian focies, while the latter are charged 

 with the remains of a fish fauna resembling that of 

 the Scottish Old Red Sandstone, It may be noted 

 that volcanic rocks are here and there associated 

 with the Devonian strata of central Europe, In 

 North America l>oth types of strata appear; the 

 arenaceous type occurring in No\a Scotia and New 

 Brunswick, while the Devonian type is met with 

 in the state of New York and tire Appalachian 

 region, and is largely developed in the Mississippi 



Life of the Period. Fucoidal markings are not 

 uncommon in the Devonian strata, but hind plants 

 rarely occur. These latter, however, are met with 

 now and again in the Old Red Sandstone, more 



esj iallv in that of Nova Scotia and New I'.iuns- 



wick, "flic chief forms are tree ferns and small 

 herlMLceous ferns, lycopods (lepidodendroids), great 

 horsetails (Calamites), and sigillarioids. Tin 

 tation would thus dp]>car to have Wii for the most 

 part flowerless. Here and there, however, remains 

 of large conifers have been detected. Among the 

 lower lorms of life that swarmed in the seas of the 

 period were rugose and tabulate corals. Of t In- 

 former the most characteristic were C\ at liophyllum, 

 Cystipbvlluni, Calccola, &c., while tne honeycomb 

 corals ( Favosites) are the most common of the tabu- 

 late forms. Echinoderms abounded, especially crin- 

 oids (Cupressocrinus, Cyathocrinus ) and pentrcin- 



