MINERALOGY. 



429 



T. Gloucester, it riaes to the height of 1124 feet above the 

 a, 



Above the/ior is the tand of the inferior oolite, which 

 is thus described by Buckland. 



Fine grained yellow, micaceous, loamy 

 sand. 



Green and yellow calcareo-siliceous 

 Msi of into- i r i 



^ sandstone, highly micaceous. 



Green and yellow "sandy marl, abound- 

 ing in large concretions, called sand 



aflk. 



f iddlt ool- 



It occurs in Gloucestershire, Somerset Jiire, tndOxford- 

 shire. 



Above till* sand, ssuditone and marl is the imfrrior 

 or buitard ontii?, described a* coarse calcareous free- 

 stone, fran*lwv with shelly p'asjaaeata, and usually fer- 

 ntgineous. It occurs around Grairtham, and in other 

 parts of England. 



Tbe inferior or Inwtnrd oolite i immediately covered 

 l>y fuller's ftrili, which tJ.mn tJie upperreost layer of 

 the lower oolite. This fuller's earth occur* iii layer* in 

 a prey-coloured day, in the middle region of kill* 

 around Bath. 



2. Middle Onlite. The lowest member of this se- 

 ries is named Great Oolite, or Krtton stone, and is 

 described as durable yettow fVeeitone, compoaed of 

 oolitic wtKMtiWM and shelly fragment*, united by a 

 <ikareou cement. It occurs at Ketton in " 



.j, of 



x'.rd 



I rag. 



tonshire, and Windrush in Oxfordshire, 

 it is the next member of the norii-i, named Slo*e- 

 Slale, which is a calcareo-silicrous oolite, some, 

 timss passing into sand, and associated with thin beds 

 of bsJcoal. The coal of Cleveland Hills, in York, 

 shire, belongs to this slate. Above the Stum field slate 

 is the Forett marble, which is a coarse slaty limestone, 

 full of large fragments of shells ( Yeovil marble,) and 

 met with nrnr Bath, and in Dorsetshire. The Cora. 

 ': rock lie* upon the Forest marble, and is a soft, 

 earthy, yellow limestone iue ajtd sandy, and 



occurs in Oxford-hire, and in Wiltshire. Ro ting on 

 tlie Corn-brash is the Kf/loirai/ rock, which is a coarse 

 sandy limestone, with many peculiar ammonites, and 

 other shells, found at Kelloway Bridge, near Calnc, 

 in U nf .. A thick deposit of clay, named Orfui 

 ml, or Fen Clay, in the next member of the series. 

 The clay is of a bluish-grey colour, an*. 

 and Urge septaria. It occurs in tin- vale of Thames, 

 from Oxford upwards ; vale of Owe, from Bedford 

 downwards ; and the vale of Blackmoor, Dorset. 



:(. Upper Oolite. The lowest anvanber of this series, 

 or that next in socesssson tS)*Jn>yp'ii>ost of the middle 

 oolite, is a ealcareout frit or tfmJtie**. It is a siliceous 

 sand and saiidatone, wit licaloareooseoient.f>t'i(M shelly, 

 and is met wkh at FiU-y. near Sosrborough, i:i York- 

 Uiire, and near Abingdon in Berks. The ii.-st iiienilwr 

 < series is Corml rag, which is a loose earthy oolite 

 limestone, full iif ooraline rrma, <mj at Ki<l<iinp- 



K-ar Oxford ; at I Ii-/lm. : and 



Kirkliy Moorsidc, Yorkshire, (liford ooKle is tlie next 

 rode of the series. It ia a perishable freestone, oompo- 

 ic rancretioMand shelly frngmrnts united by 

 a calcareous cement. It occurx at I li-lilin^tmi in Ox- 

 foroWure : ''-ilts; and New Malton, York- 



Ktrnmtndgt clay is the rock next in fucccmion. 

 a Uiie slaty clay, with selcnite, and w sonetimes li^li- 

 ly JttumJn..u.s : Occurs at the bane of Shotnu r Mill, 

 near Oxford ; in the island of Portland ; and t Kim- 

 mecadge, in isle of Purbock, Dorset. Above the Kim. 

 mtsidge day is the 1'ortUnd Hone, which is a oalca- 



reo- siliceous durable freestone, often oolitic, containing Geognosy. 

 beds and nodules of chert. It occurs in the isles of ""Y"" ' 

 Purbeck and Portland ; Chilmark, Wilts ; Twindon ; 

 Aylesbury. The uppermost rocks of the series are the 

 Piirhe/ck btdt. These are strata of slaty clay and marl, Purbeck 

 alternating with beds of coarse shelly limestone. They " ne - 

 occur at Sandwich, Lulworth Cove, and Upway, Dor- 

 set ; Lady Down, near Tisbury, Wilts. 



IV. Fourth Secondary Limettone, or Chalk. 



Kreidc- Gebirge. H 'erne r. 

 Formation crayeuse. Da*b*iuo*. 



Fourth 

 tecondarr 



limestone 

 or chulk. 



This formation consists of three members, viz. chalk Chalk marL 

 marl, hard chalk, and toft chalk. 



1 . Chalk mart. This is an argillaceous grey-colour- 

 ed chalk, without flints or chert, pacing into a finemi- 

 caoroiu grev fcand, or into a grey marl or clay. It 

 upon the third sandstone formation, which therefore 

 separate* it from the oolite formation. It occurs at 

 Bsusjon in Oxfordshire; Cherhill and Norton, iJcv.uit, 

 Wilta ; Lewes ; Guilford ; Folkstone ; Byarsh near 

 U'rotham, Kent 



2. Hard Ck*lt, or T^trer Chalk. This chalk is hard- Hirdehalk, 

 er than that w^ich forms the upper part of the forma- or !owcr 

 bon, ami i sometimes of a brick-red colour. It con. clulk< 

 uins fisw flint* or petrifactions. It occurs near War. 

 misistei, Shakespeare's Cliff, Dover; Flamborough 



Head, Yorkshire ; county of Antrim, Ireland. The 

 red varieties enir in Lincolnshire and Yorkshire. 



3. Gflfi Chalk, or I 'pptr Chalk. This is the common Soft chalk, 

 chsdk oif minentlogwts, which is soft enough to mark or upper 

 with. It *entainii abnndanee of (lint, in the form of ch>u ' 

 HftMroso, roundish, and ovoidal masnes, either irregu- 

 larly dirtrilnitctl in the mass, or disposed in horizontal 



layer* ; the flint is sometime* also arranged in beds, 

 which occasionally extend, without interruption, for 

 more than a mile ; and, in other cases, veins of flint tra- 

 Trse the chalk in all directions. The flinty masses are 

 sometime* hollow in the centre, and the walls of the 

 cavities lined with crystals of common quartz. The 

 petrifaction* found in the chalk and flint are bclem* 

 ntlos, echinitei, alcyonkes, spongites, oftracitts, pec- 

 tioiics, terebratulites, ammonites, plagiostomites, mil. 

 Irporitet, &-c. ; also teeth and palates of li-hcs of the 

 shark tribe. At the hill of St. Pierre near to Mnrftricli, 

 the remains of a species of monitor hare bvcn found in 

 a kind ot'rli.ilk. 



Both the hard and soft chalks occur stratified : the strata Stratifica* 

 are yestefalty horizontal ; sometimes inclined at a con- lion - 

 siderabt* angle, or even perpendicular ; and there are 

 instances, at in the Isle of Wight, of |>erpendicular 

 strata meeting with horizontal, and also of horizontal, 

 or slightly inclined strata resting on vertical strata. 

 Metalliferous minerals occur rarely in this formation, Metallife- 

 and almost the only species hitherto met with is iron roui mine, 

 pyrites, which is sparingly disseminated through the ' 

 chalk. 



'/CT/.on. It rests upon the third sand. Geognottlc 

 stone form Mi ..n situation. 



Gographic f>i!natinn.Ck:t\k does not occur any Geographic 

 where in Scotland, but in Kngland it forms extensive situation. 

 tiacts of country, and has l>een tracetl tu.m near Si<l- 

 mouth in Devon>liirt- to I iley Bay in Yorkshire. It also 

 occurs in Ireland, as in the county of Antrim, t'h.-tlk 

 forms a considerable portion of the mirth of France ; it 

 also occurs on the shores of the Baltic, in the Danish 

 islands, in Hohtein, Mecklenburg, and Pomerania; it 

 constkntfs the principal rock formation in Poland and 

 in southern Russia ; and has been found iu the Crimea. 



