192 ORGANIC REMAINS. 



These petrifactions may be seen in their most perfect state, in a 

 recess on the shore between Riinswick and Staiths, from whence this 

 specimen, Fig. 9, was taken. They lie in a kind of beds or seams, 

 covering some of the bands of ironstone which we have named the 

 Kettleness beds. They are found in similar situations in other parts 

 of the coast. We also meet with them in the ferruginous sandstone 

 of the Scarborough and Cayton shores, and in some of the hard 

 sandstone beds at Filey Bridge. 



The existence of iron in most places where these remains are 

 found, may occasion some doubt as to their vegetable origin. It has 

 been already remarked, that metallic solutions often assume arbores- 

 cent forms, and we know that depositions of iron at chalybeate 

 springs are sometimes curiously ramified, and that ferruginous matter 

 frequently sinks down in clayey beds, where it hardens in the form of 

 roots of shrubs : but the bodies now under consideration seem far 

 too uniform in their size, shape, and arrangement, to admit the 

 supposition of their having been produced in the same way. Besides, 

 undoubted petrifactions of wood, and other vegetable substances, 

 are often found impregnated with iron, or even imbedded in iron- 

 stone, the iron lending its aid in preserving them ; and this has 

 probably been the case in the present instance. 



Some have described such bodies as spongites ; but it is more 

 likely, that they are the remains of marine plants. It is possible, 

 however, as some of the sponges branch out in a similar way, and 

 as sponges are found to grow among marine plants, that the 

 petrified substances, found in the situations now mentioned, may 

 consist partly of both. 



