:k 



isvi 



'// 



'My 



FLINT AND CHERT. 



65 



\ 



ndstont, 



i 



selves suggestive of their origin, and when properly sliced. Upper 

 polished, and examined with the microscope, the minuter A ^ KY# 

 structure becomes apparent. — A. C. R. A\ all-case 42 



1. — Two specimens of flint from the Chalk. 



™*g8 from 2 > 3# — Chalk flint, the interior lined with mammillated 



wthefito. chalcedon y- 



dport 



n >. JVa 



m 



4. — Chalk flint. — Freshwater Bay, Isle of Wight. 

 5. — Chalk flint, showing surfaces fractured prior to its 

 deposition in the drift. — Hitcham. 



6. — Chalk flint. 



i 

 \ 



nd stone, 



markings. 



■7 



Chalk flint. 



Down, Isle of 



of Wigh 



8. — Large specimen of chalk flint ; apparently, from its 

 stained exterior, from tertiary beds immediately overlying 

 a denuded surface of chalk. 



10. — Flint, showing an agatiform structure dissected out 



elief the cra( 



icesterimK on a f ra ctured surface. 



, 171, 181) 



o 



iff ham, Nor ft 



11. — Flints, with white spots, and exhibiting a charac- 





teristic conchoidal fracture. 



iff ham, Norft 



.jdalmarfc 12. — Chalk flint, containing the cast of a decomposed 



sponge 



Down, Isle of Wigh 



13. — Three specimens of chalk flint, containing easts 



of decomposed sponges. 



Down, Isle of 



14— Flint, with a fossil shell (PI 



) 



B& c° nt * 



$ 



attached to its outer surface. — From the Upper Chalk, 

 Arreton Dozen, Isle of Wight. 



15. — Chalk flint, the interior lined with minute crys- 



tals of quartz. 



Down, Isle of W 



X00SO* 



16. — Chalk flint, from the junction of Chalk and 



Lower Tertiary, showing the peculiar green stains, 



fre- 



are *■ , 



W?\ 



quently characteristic of flints occurring at the base of the 



o* 



■ctW 



Tertiaries. (S 



ofD 



S tu diet nd Bar/, coast 



fins 



*> 



17, 18. 



bo 



di^ 



> ^ 



■ 



Chert, overlying the sandstone beds Nos. 55 



of Upper Green- Sand. Used for 

 road material, for which, from its hardness and toughness, 

 it is well adapted. 



(Wall-case U) 



are 



o^ 



ftesbury Do 



C 



