574 



IMBEDDINa OF AQUATIC SPECIES 



[Ch. XLVIII. 



more sand as to prevent the rays of the sun from penetrating, 

 so that the jolk was chilled and deprived of vitality. The 

 shells were perhaps slightly broken at the same time, so that 

 small grains of sand mi ' ' 



interior by water as it percolated through the beach. 



Marine testacea. — The aquatic animals and plants which 

 inhabit an estuary are liable, like the trees and land animals 



Eig. 145. 





s.- 





rr 



^'^:, 



v^-< 



>; 







rtdlV 



i^^ 



y^.y>' 



t - 



^.^. 



\->Xa 



V- 



\^\ 



y- 





^yi^^ 



^w„/, 



^i^ 



■>-- 



yy 



7 



T 



V 



•<U^- 





\ 



iji. 



'X'-k 



\ 





\\\ 



N 





t 



lG-1 



V. 



^* 



? 



^r^: 



- ' ■> 



?^ 



■■i-r"^ 



h^{C7 







**>^iV-:-r: 





;v: 



'if: 



\^ ^T^l 



^-l 



i . --f-.' 



'IJ^^- 





V: 





1'^ 





^'"\W 



.X 9 ^ 



lM" 



£c 



'-^ 





V. 



'''■%. 



V« 





I ^'r} V*- 



I 



?. 



'" 



W^ri 



■Jl 



"i Vw*?^ 



\^1 



rf 



i^Ti 







'-^:;^it^ 



^>^ 



^.B:if 



?^ 



'\^ 



v^ 



rr ,-* 



.^ 



I? 



:i- 



.'V 



-r>^; A^r 



■%-i 



^, 



m.^ 



oP 



\t'k 





1-.: 



V- 



?^. 



'^- 



'^y 



■y 



'c-J". 



^^ ^ 



r^;- t-'_ 



;^^- 



>v: 



r'. 



t*r 



^i^^ 



I " ^ 



-V^ 







r:^: 



'^i*^. 



*■- 



<^^ 



^^1=^5^ 



r; 



^_.>'^' 

 "^^^^r? 



^'' 



?v: 





L-X* 



*:.', 



-f 





Vr 



.^ 



J< 



'-/ 





^S^fX^ 



y — 



'C-; 



^ 



^/V/ 



/ 



>r^jl 



'^J, 



^,<' 



Si^ 



-6t 



MM 









^ J-^ 



t 



■^ /^ 



<i,w: 



,^: 



:»^ 



One of the eggs in fig. 144, of the natural size, showing the bones of the fcetus which had 



been nearly hatched. 



which people the alluvial plains of a great river, to be SAvept 



from 



a river is per- 



petually shifting its course, and undermining a portion of its 

 banks with the forests which cover them, so the marine 

 current alters its direction from time to' time, and bears a.wa.v 



mud 



ty 



lliese banks may consist in great measure of shells peculiar 

 to shallow and sometimes brackish water, which may have 

 been accumulating for centuries, until at length they are 



of the sea, at 

 id multiplied. 



bottom 



Thus littoral 



mor 



even than freshwater species, to be intermixed with the ex- 

 uvise of pelagic tribes. 





