2/2 JURASSIC. 



best seen in the cliffs east of Seatown, under Down Cliff, and Tiiorncombe Beacon. 

 Fossils are readily to be obtained from the fallen masses on the shore, but it is a 

 matter of no great difficulty to trace them out in sitti. The Starfish-bed will be 

 easily recognized on the shore from its smooth surface, and the numerous oblong 

 or square hollows which mark the places from which starfishes have been chiselled 

 out by the fossil collectors. The junction-bed of the Middle and Upper Lias is 

 very ferruginous, but its creamy and pink portion clearly distinguish it from a bed 

 of fossiliferous brown sandy limestone (containing Gryphcra cymbinm and Pecten 

 CEquivalvis), which occurs at a lower horizon, and is abundantly strewn on the shore. 



Inland in Dorsetshire many charming lanes are excavated 

 deeply in the rock-sands of the upper part of the Middle Lias ; 

 but from the examination of an isolated section it is very hard to 

 distinguish the sands at the base of the Inferior Oolite, from the 

 sands that occur in the Middle Lias series below the Marlstone or 

 " Rock-bed." 



In Somersetshire the Middle Lias is tolerably persistent in the 

 escarpment below the Oolites. It is found at Ilminster, north- 

 west of Yeovil, Glastonbury, Pennard Hill, and Brent Knoll ; 

 it is rarelv exposed between Castle Gary and Bath. (See Fig. 

 39.) At Whatley, near Frome, thin beds of IMiddle Lias, yielding 

 many fossils, have been found by Mr. Moore. ^ (See Fig. 41, 



P- 25^) 



In the Gotteswold Hills the Middle Lias has a thickness of about 

 120 feet, the Rock-bed being 12 to 20 feet; at Bredon Hill the 

 total thickness is 310 feet; at Wotton-under-Edge the Rock-bed is 

 12 feet, and the lower strata 186 feet. (See Fig. 44.) The 

 Middle Lias may be studied also at Alderton and Dumbleton, 

 between Tewkesbury and Evesham, at Gretton, Church Down, and 

 Hewlett's Hill, Cheltenham, and also at Stroud.^ 



In Oxfordshire the lower beds, about 10 to 20 feet in thickness, 

 consist of sands, clays, and sandstones ; and the rock-bed, with 

 much iron-ore, is from 6 to 12 feet in thickness. Mr. T. Beesley 

 observed (1873) that for a long time past attempts have been made 

 to introduce the Marlstone of this district as an available ore of 

 iron; but it is only since the year 1870 that these attempts have 

 met with success. Extensive excavations have been carried on 

 at Adderbury and King's Sutton, south of Banbury ; in the valley 

 of the Evenlode, west of Charlbury, and at Fawler, west of Stones- 

 field. The ore, known as the Blenheim iron-ore, contains about 

 31 per cent, of iron. Terebratula punctata and Rhynchonella 

 tetrahedra occur in the ironstone.^ In the neighbourhood of 

 Fawler the clays with Ammonites margaritatus repose on similar 

 clay with A. capricornus.^ 



In Northamptonshire the Middle Lias is about 40 feet in thickness, 

 and is exposed to the south-west of Northampton, between that 



1 Q. J. xxiii. 476. 



2 F. Smithe, Proc. Cotteswold Club, vi. 349 ; Witchell, Geology of Stroud, 

 p. 17. 



3 T. Beesley, Proc. Warwick Nat. Club, 1872, p. II ; Hull, Geol. Woodstock 

 (Geol. Survey), p. 9. 



* F. A. Bather, Q. J. xlii. 144. 



