m, 



ntoj 

 if? 



■>' 



it: 



i 



,; 



It 





mei: 



JL.1L 



m 





)ari 



i 





i 





CLEAVAGE, ETC. 



123 



therefore, oft 



>/ 



,„_, ^«,,„ y „„ we uirecnon or the 

 pressure, so that for^e &><#«, in many cases, become visibly 

 compressed, often flattened, and n^^r,Jh. ™„.„i j- ,. . , ., 



"Wall-case 46. 



i« x .- x. • ' — yw.i, ,c*^y muvn distorted, the 



distortion, for instance, sometimes elongating, and at other 

 times broadening fossils far beyond their ordinary dimen- 

 sions, and frequently giving an unsymmetrical shape to 

 ™" + " + in their natural state are quite symmetrical. 



forms that 



„,.. UUHII ^ aio quite sy 



The true slaty structure in rocks is always the 



cleavage. 



>f 



26. 



of Snowdon, Caernarvonshire. Map 75 N 



felspathi 



r fi 



27. 



flabellulum) 



•• Top 

 Part of the 

 Cleavage crosses 



the fossils (chiefly 



fom Caernarvonshire. Map 



.B 



-Pass o/*Z/< 



Imp erf i 



The beds dip at angles of about 60° to 70°, and the cleavage 



(cleavage, 70° to 80°.) 



form an angle of 



28. — Slate, Upper Devonian, ft 

 coincident with bedding or nearly 50. 

 flattened and much distorted. 



29.— Clay slate, Upper Devoni 



ifi 



leavage 



Petherwyn, Devonsh 

 angle of about 10°. 



distorted by cleavage. 

 30. 



Cleavage 



(carboniferous ?) 



Cleavage and bedding coincident, 

 tened and very much distorted. 



Strophalosia caperata flattened and 



Upper Devon 



an, Tintagel, Cornwall. 

 Spirifer disjunctus flat- 



I 



fitn rift™ 10 B0 ° K ' """^tionanj, west side 



anH K H f V ' "' Frm °° n - M <>P 78 S.E. Cleavage 



and bedd,„ g form an angle of 19". Bedding and cleavafe 

 struet^ "5? " Wgh a °« leS - Shws ' coneretionafv 



