OLD RED SANDSTONE 



OLEANDER 



595 



itea. Trilobites, which formed so marked a feature 

 in the life of the Silurian seas, were now reduced 

 in niimlier anil variety among the more notable 

 forms being Phacops, Hornalonotus, and Bronteus. 

 Some of the eurypterids (most of which are small) 

 attained a large size, one of these ( Pterygotus ) 

 bein<r 5 or 6 feet long. They <*cur chiefly in 

 the Old Red Sandstone. From the same strata in 

 North America have come the remains of insects 

 neuropteroid and orthopteroid wings of ancestral 

 forms of May- fly, &c. Myriopods have also l>een re- 

 cognised. Brachiopods are among the most common 

 Devonian fossils ; indeed this group appears to have 

 reached its maximum development in the seas of 

 iliat period. Very characteristic forms are Uncites, 

 Stringocephalus, and Kensseleria. Lamellibranchs 

 were well represented, some of the notable genera 

 lieing Pterinea, Megalndon, Cuculltea, Avicula, &c. 

 The marine gasteropoda call for no particular men- 

 tion, for they belong chiefly to types which had 

 come down from earlier Palaeozoic times. One 

 may note, however, that the earliest pnlmonates 

 (Snails, &c. ) come from the Old Ked Sandstone. 

 The straight Orthoceras and other old genera of 

 cephalopods continued to flourish, but coiled forms 

 (Clymenia, Goniatites) began to predominate in 

 Devonian times. From the Old Ked Sandstone 

 chiefly come the remains of numerous ganoid fishes 

 a group feebly represented in existing waters. 

 Among these are tne placoganoids Cephalaspis, 

 Pteraspis, Pterichthys, and Coccosteus, and the 

 lepidoganoids Osteolepis, Diplopterus, Holopty- 

 chins, Acanthodes, &c. The largest placoga- 

 noid was the Dinichtliys of North America the 

 armoured head of which was 3 feet in length. 

 According to Dr Newberry, this fish was prolMvbly 

 not less than 15 feet long, 'encased in armour, 

 and provided with formidable jaws, which would 

 have severed the body of a man aa easily as he 

 bites off a radish.' Other forms (such as Dipterus, 

 and possibly Phaneropleuron ) appear to have rela- 

 tions with the modern mud-hsh (Ceratodus) of 

 Australia. 



It is obvious that in the Old Red Sandstone and 

 Devonian we have two distinct types of sedimenta- 

 tion ; the two series must have accumulated under 

 different physical conditions. The Devonian strata 

 are unquestionably of marine origin, while the Old 

 Red Sandstone lieds are believed to have been 

 deposited in large lakes or inland seas. Hence we 

 meet with the latter in a few more or less isolated 

 basins, while the former extends over enormous 

 regions. From the geographical distribution of the 

 marine Devonian in Europe we gather that during 

 the period in question the sea covered the south of 

 England and the north-east of France, whence it 

 extended eastwards, occupying the major portion 

 of central Europe, and sweeping north-east through 

 Russia, and how much farther we cannot tell. 

 North of that sea stretched a wide land surface, in 

 the hollows of which lay great lakes and inland 

 seas, which seem now and again to have communi- 

 cated with the ocean. It was in these broad sheets 

 of water that the Old Red Sandstone strata were 

 accumulated. Several of these old lakes in Scot- 

 land were traversed by lines of volcanoes, the relics 

 of which are seen in many of the hill-ranges of the 

 central and southern regions of that country. Vol- 

 canic action also at the same time manifested itself 

 in some parts of Germany, but on a smaller scale 

 apparently than in the Scottish area. The land, 

 as we have seen, was clothed for the most part 

 with a monotonous flowerless vegetation, but large 

 pines grew on the higher and drier uplands, whence 

 they were occasionally carried down by rivers to the 

 lakes and seas. Very little is known of the terres- 

 trial animal life of the period ; most of the fossils 

 met with in the lacustrine sediments of the period 



consisting of the remarkable ganoids and eury- 

 pterids already referred to. These (the fishes 

 especially ) appear to have abounded in the lakes, 

 whence, however, they now and again descended 

 by the rivers to the sea. The general facies and 

 the geographical distribution of the life of the 

 Devonian and Old Red Sandstone are suggestive of 

 genial climatic conditions. Some geologists, how- 

 ever, have thought that the coarse breccias and 

 conglomerates which occur in the Old Ked Sand- 

 stone may lie indicative of somewhat cold condi- 

 tions ; for these masses have often quite the aspect 

 of morainic accumulations. It is possible, there- 

 fore, either that local glaciers may have existed in 

 certain regions, or that the temperature may have 

 l>een lowered for some time over wider areas. 

 However that may l>e, the presence of the Devonian 

 fauna in the Arctic regions seems to show that the 

 temperature of the ocean must have been more 

 equable in Devonian times than it is now. 



Old Sarniii. See SARUM. 



Old Style. See CALENDAR. 



Oldys, WILLIAM, an industrious bibliographer, 

 was a natural son of Dr Oldys, Chancellor of 

 Lincoln, and was Ixirn in 1C96. The most of his 

 life was spent as bookworm and bookseller's hack. 

 He suffered by the South Sea Bubble, lost the 

 property left by his father, and when he died 

 (April 15, 1761) left hardly enough to decently 

 bury him. For about ten years Oldys acted as 

 librarian to the Earl of Oxford, whose valuable 

 collection of books and MSS. he arranged and 

 catalogued, and by the Duke of Norfolk he was 

 appointed Norroy King-of-arms. His chief works 

 me The liritish Librarian (1737, anonymously); a 

 Life of Sir Walter Raleigh, prefixed to Raleigh's 

 History of the World (1738); The Htirleian Mis- 

 cellnny (8 vols. 1753), besides many miscellaneous 

 literary and bibliographical articles. 



Oh'acCJP, a natural order of exogenous plants, 

 consisting of trees and shrubs, with opposite leaves, 

 and flowers in racemes or panicles. Nearly 150 

 species are known, mostly natives of temperate 

 countries. Among them are the olive, lilac, privet, 

 phillyrea, fringe tree, &c. Between some of these 

 there is a great dissimilarity, so that this order is 

 apt to be regarded an a very heterogeneous group ; 

 but the real affinity of the species composing it is 

 manifested by the fact that even those which seem 

 most unlike can be grafted one upon another, as 

 the lilac on the olive. Bitter, astringent, and 

 tonic properties are prevalent in this order. 



OH'SHlder ( A'eri'wjn ), a genus of plants of the 

 natural order Apocynaceoe. The species are ever- 

 green shrubs with leathery leaves, which are oppo- 

 site or in threes ; the flowers in false umbels, 

 terminal or axillary. The Common Oleander (A r . 

 oleatider), a native of the south of Europe, the 

 north of Africa, and many of the warmer temperate 

 parts of Asia, is frequently planted in temperate 

 countries as an ornamental shrub, and is not un- 

 common in Britain as a window-plant. It has 

 beautiful red, or sometimes white flowers. The 

 English call it Rose Bay, and the French Rose 

 Laurel ( Laurier Roue ). It attains a height of eight 

 or ten feet. Its flowers give a splendid appearance 

 to many ruins in the south of Italy. It delights 

 in moist situations, and is often found near streams. 

 All parts of it contain a bitter and narcotic-acrid 

 juice, poisonous to men and cattle, which flows out 

 as a white milk when young twigs are broken off. 

 Cases of poisoning have occurred by children eating 

 its (lowers, and even by the use of the wood for 

 spits or skewers in roasting meat. Its exhalations 

 are injurious to those who remain long under their 

 influence, particularly to those who sleep under it. 

 A decoction of the leaves or bark is much used in 



