

' tlle atte^ 

 A «stri a „ ; 



I'plomentt, 



RIPPLE-MARKS AND SUN-CRACKS. 



63 



1 'gy," 



subjacent older rocks, partly on Carboniferous limestone, Upper 

 and partly on Old Red Sandstone. Galleby. 



" Not only is a large portion of the area, wherein the Wall ' case 41 « 

 Inferior Oolite is seen to rest on the Carboniferous limestone, 

 observed to have presented a marked even surface, viewed 



P' & on the 



large 



scale, for the deposit of the former, but, 



throughout, this surface has been drilled into holes by 

 the t lithodomous animals, which must have existed in the sea at 

 > w.~Li the commencement of the Inferior Oolite. The holes which 



were observed by Professor John Phillips, in 1829, arc of 

 «rbeck; k two kinds, one long, slender, and often sinuous, extending 



several inches into the carboniferous limestone, the other 

 rlston Bay, entering that rock a short distance only. In the former we 



find no traces of shells, in the latter we often discover them 

 hells. : in the situations in which they lived. In both holes we 

 e late Pro- find the matter °f the Inferior Oolite, which entered them 

 he Echinof from above at il ^ time of its deposit."— Do la Beche. 



?et thick, i 



r s 



( See % 



178.— Purbeck limestone, the surface of the bed covered 

 with ripple marks, Cypris, &c. From the Cypris shales of 



of sand « the Upper Purbeck 



01 



d M 



U 



of Purbeck, Do 



.prese 



(See Vertical Section, No. 22.) 

 1 79.— Permian sandstone, exhibiting a combination of 



(See 



Lennox 11 ; ripple marks and sun-cracks.— Atherbury, Salop. 



64) 



, Sun-cracks in rocks have been frequently formed 

 ; result o on soft strata, lying probably between high and low water 

 rea part « mark. In such cases the cracked and dried lines have been 

 it jppftf filled after an interval by other sediment, sometimes finer, 

 - : sometimes coarser than the surface on which the crack was 



made, and it therefore happens, that after entire consolida- 

 tion, when the strata are split, the lines of the original 

 cracks become visible, and often on the bottom of the upper 

 bed stand out in relief— A. C. R. 



180.— Ripple marks, annelid tracks and sun-cracks on 



ts 



them 



uliar 



.,1 W 

 „ i0 r 



. 





» 



,urve)' 

 on*' 1 '" 



House 



Keuper Sandstone. 



181. —Ripple marks and sun-cracks, from the Lower 

 Lias Limestone. This specimen consists of two beds on the 



