OOLITE. 



OOLITE. 



5. The Great Oolite is separated from the iiext bed, containing 

 amongst them the clay used in the manufacture of cloth under the 

 name of Fuller's Earth, and also a thin calcareous flag-stone known 

 as the Stonesfield Slate. The latter is remarkable for containing the 

 remains of Marsupiate Animals. [MARSUPIATA.] 



6. The Inferior Oolite ia the last of the series of oolitic limestones. 

 It is employed to a great extent as a building material. Its represen- 

 tative in France is the Caen Limestone. 



The oolitic system embraces also the formation called Lias. In 

 England it- consists of a series of strata in which an argillaceous 

 character predominates throughout ; it also contains limestone mixed 

 with clay. It seems to form four principal members, which are thus 

 described by Professor Ansted. 



" The Upper Lias, or Alum-Shale, is best seen at Whitby, and on 

 the Yorkshire coast, and it attains there a considerable thickness. It 

 consists of three distinct parts : the lower division including soft 

 shales, extremely fossiliferous, which are separated from the upper- 

 most series, also composed of incoherent slaty beds, by an interme- 

 diate stratum of hard shale, about 30 feet thick, containing a quantity 

 of the mineral called jet, and also occasionally large fragments of the 

 bitumenieed wood of coniferous trees. The jet itself is but a peculiar 

 form of carbon, and there can be little doubt that it is of organic 

 origin. It is in the upper shales of the lias, both on the coast of 

 Yorkshire and at Lyme Hegis, that there have been found the most 

 remarkable and interesting of those fossil remains of extinct animals, 

 for which the formation ia so celebrated. The presence of alternate 

 bands of tolerably hard limestone and soft shale is usually charac- 

 teristic of the lias in the different parts of England where it is most 

 developed. The dark bluish-gray colour, united with the singular 

 riband-like structure, is more particularly remarkable in the upper 

 beds of the formation, and a well seen at Lyme Regis, Whitby, and 

 Barrow-upon-Soar, in Leicestershire. 



' The principal locality of the middle beds of the lias is the neigh- 

 bourhood of Cheltenham, where the marlstone of Dumbleton Hill is 

 crowded with interesting organic remains. It ia made up of alternat- 

 ing layera of coloured claya and sands, which are occasionally 

 calcareous, and of beds of impure limestone. 



" This part of the series ia also represented in the north of England, 

 where it has an average thickness of about 130 feet, and consists of 

 sandy shales, of which the upper portions are distinguished by the 

 presence of several bands of argillaceous irony nodules. 



" Lower Lias Shale. The great mass of the lower division of the 

 Lias is found in the middle of England, and consists of thick beds of 

 dark coloured and finely laminated shale, iu which are calcareous 

 bands and concretions. These form the base of the series, and 

 graduate downwards into a whitish sandstone, belonging to the upper- 

 most beds of the New Ked-Sandatone system. The transition is 

 clitl'erent again in the south of England ; and at Lyme Regis marls of 

 a light-bluish colour represent the upper beds of the New Red-Sand- 

 stone and pass into the Lias Limestone by a succession of dark slaty 

 marls, which are overlaid by a number of gray calcareous beds, and 

 these again by other slaty marls of the upper series. The Marlstone 

 and Upper Lias Shales are not present in thia part of the deposit in 

 their ordinary form. 



" The lowest portion of the Liassic System occasionally consists of a 

 very thin bed, in some places entirely made up of the fragments of 

 fossil bodies (chiefly the remains of fish), but sometimes passing into 

 a white micaceous sandstone, still recognisable as the same bed. 

 This bed was first observed underlying a small patch of Lias, near the 

 town of Aust (situated on the left bank of the Severn, nearly opposite 

 the mouth of the Wye) ; but it haa since been recognised at Axmouth, 

 in Devonshire, and in other parts of England farther north, having a 

 total range of upwards of 100 miles. It is rarely more than 2 or 

 3 inches in thickness, but invariably occupies the same geological 

 position, and ia for the most part so exclusively composed of organic 

 remains, that a long period must have been required for its formation. 

 In some parts of the country, and especially in Gloucestershire and 

 Worcestershire, the passage of the Lias into the underlying beds of 

 New Red-Sandstone ia marked by the presence of calcareous flagstones, 

 called Lower Lias Lime-tones; and these usually alternate with 

 laminated shales, the whole in that case forming together the lowest 

 its of Lias. 



" On the Continent the Lias is frequently found, and the upper beds 

 resemble those developed in England ; tne middle however are usually 

 more calcareous, and the lower more sandy, and these latter some- 

 times, as in Belgium, pass insensibly into the upper New Red-Sandstone. 

 The town of Luxemburg is built upon a hard sandstone of this kind, 

 and these bed* pass into the rock called Arkosc, a peculiar and often 

 metalliferous metamorphosed deposit, occurring where the Lias sands 

 comn in contact with crystalline rocks. Fossils have been found in 

 South America, and also in Northern India, attributed to the period 

 we are now considering. 



" The Lias is a formation exceedingly rich in fossils ; and amongst 

 them are representatives of all the principal natural groups. Corals 

 however are excee<lm_'ly rare, and of small size. Encriuites are 

 ions and abundant, especially the Pentacrinitc, which attached 

 itself to floating wood. Rudiutcil animals of other kinds characterise 

 parts of the deposit*, and of these the JJiademtt is an example. 



Insects and Crustaceans have been frequently found. Star-Fishes are 

 common in the marlstone. 



" Both univalve and bivalve shells of various kinds are characteristic 

 either of the whole deposit or of different beds. The Spirifer ia one 

 of the later species of a genus represented far more abundantly iu 

 more ancient deposits, while the Plicattda and Playiostoma are among 

 the ancient representatives of more recent forma. The Pecten is an 

 example of a similar kind; and the Ammonite and BdemnUe are 

 eminently characteristic cephalopodoua shells, infinitely abundant 

 during the Lias, and scarcely less so for a great part of the oolitic 

 period. Above 170 species of MMusca have been described from the 

 British localities only, of which as many as 70 are Ammonites. 



" Fishes' remains are common in some parts of the Lias, and as many 

 as 60 species in all have been described ; of these many resemble the 

 shark, but none seem to have attained very gigantic proportions. 

 This however was not the case with the Reptiles, which during the 

 period in question, were equally ' remarkable for their large size, vora- 

 cious habits, and incredible abundance. Many apecies belonging to 

 natural orders of these animals long since lost, were theu widely 

 dispersed ; and many other species, existed of genera now common iu 

 distant parts of the world. The Flying Reptile [PTERODACTYL] is a 

 striking instance of anomalous structure. The swimming and indeed 

 strictly marine monsters named Ichthyosaurus and Pleaiosuurui, are 

 other examples." [ICHTHYOSAURUS ; PtESiosAcnns.] 



The following is a list of the Fossil Genera found in the Oolitic 

 Beds: 



Plants. 



Alelhopterii, 2 species. Peuce, 2 species. 



Araucaritea peregrinus, Prejl. Pldebopteris, 2 species. 



Benaonia ovata, Buck. Polypodites, 2 species. 



Brachyphyllum mammillare, LmdL Polijsticldte* Murrayana, Presl. 

 llticklandia tquamoia, Brong. Pteruphyllum, 4 speciea. 



Carpolithei, 3 species. Salicitcs longifolius, Buckm. 



C'ydupterit, 2 species. Solenites, 2 speciea. 



Dictyophyllmn ruyoium, Liudl. Sphareda paradoxa, Liudl. 



i'yuuetita, 2 species. ^jilicenopteris, 6 species. 



LUia lanceolata, Buckin. Sp/icrococcitei, 2 species. 



Lycopoditet, 2 species. Stricklandia, acuminata, Buckm. 



Naiadea, 2 species. Strobilitet elongata, Liudl. 



Neuropterii rccentior, Linill. Tamiopteris, 3 speciea. 



Olopterii, 2 apecies. Thuytti, 4 apecies. 



Paekj/pttrit, 2 species. Tympauoihora, 2 species. 



Pecopterit, 11 species. Zamitts, species. 



Amorphozoa. 

 Sponyia, 7 species. 



Alecto dichotoma, Lamx. 

 Aapendtsia criitata, Lamx. 

 Ayaricia lobata, Goldf. 

 Aitrea, 5 species. 

 Caryophyllia, 2 species. 

 Ceriopora clavata, Goldf. 

 Chryiaora, 2 species. 

 Cricopora, 2 species. 

 JJiattopora, 3 species. 

 Eunomia radiata, Lamx. 

 J-'ungia orbulitct, Lamx. 



Zooptiyta. 



Jlcteropora, 2 species. 

 Idmonea triquetra, Lamx. 

 Intricaria Uajocensis, Bronn. 

 Litfiodendt'on eleyans, Goldf. 

 Madrepora limbata, Goldf. 

 Meandrina Soemmeringii, Goldf. 

 iliilepora, 2 species. 

 Montliraltia, caryophyllata, Lam. 

 Terebellaria ramoiissima, Lamx. 

 Theonoa clathrata, Lamx. 

 Turbinolia dispar, Phil. 



Echinodermata. [ECHINODERMATA.] 



Annelida. 



Serpula, 17 species. Vermicularia, 5 species. 

 Vermilia sulcata, Sow. 



Clrripedia. 

 Pollidpts, 3 species. 



fnsecta. [INSEOTA.] 



Crustacea. 

 Aitacm, 4 species. 



Conchifera Monomyaria, 



Amphidesma, 3 species. Lulraria, 5 apecies. 



Anatlna undulata, Sow. sp. Li/sianatsa, 4 specie*. 



Area, 9 species. Mactromya Cardioidei, Phil. sp. 



Aitarte, 16 species. ifodiola, 17 species. 



Cardinia, 12 species. Mya, 3 apecies. 



Cardium, 12 specie.'. Myuccncha crattsa, Sow. 



Corbie, 3 apecies. Mytilits, 4 apecies. 



Curbula, 4 species. NuciUa, 11 species. 



CutciUlcea, 14 species. O/n's, 2 species. 



Cypricardia lolida, Lycett. Panopoea, 3 species. 



Cytherea, 2 species. Pectunculun, 2 speciea. 



Qattrocliitna tortuona, Sow. Pholadomya, 19 species. 



Qi'Uilya Anglica, Ag. . Pltolcu, 2 species. 



fftppopodimi ponderotuin, Sow. Pinna, 8 species. 



Itucardia, 11 species. Psammobia lievigata, Phil. 



/." '.inn, 4 species. PMiutra (1), 4 species. 



