400 THE CARBONIFEROUS SYSTEM. 



and, in a bed of sandstone a little to the northward of the village, mag- 

 nificent examples of Sigillaria stumps, with their roots and rootlets at- 

 tached, are seen in situ. The beds dipping seawai'd at a small angle, and 

 undergoing rapid waste, expose these stumps on a horizontal surface, 

 and not in a vertical cliff as at the Joggins ; and this affords great 

 facilities for studying the arrangement of their singular roots. Some 

 of the stumps are two feet and a half in diameter, and may be seen to 

 give off their pitted Stigmaria roots in four main divisions, exactly at 

 right angles to each other, each main root subdividing regularly into 

 two, four, and so on. They are in the state of casts in hard calcareous 

 sandstone, and they have grown on a soil consisting of loose sand, 

 now sandstone, and stiff clay, now represented by beds of shale. Some 

 of the layers of sandstone immediately under the roots are distinctly 

 ripple-marked, and must, when the trees grew on them, have been 

 either very recently elevated from the sea-bed, or must have been 

 layers of blown sand. If it were not for the general uniform bedding 

 of the Coal formation sandstones embedding these plants, an observer 

 would be strongly inclined to refer them to the latter cause ; and I 

 think it by no means impossible that some of them may have had such 

 an origin, and may have been afterwards smoothed and levelled by 

 water, before the overlying beds were deposited on them. 



More than one generation of these trees have grown on this spot, 

 for I observed one of the stony trees to be penetrated by a cast of a 

 Stigmaria with rootlets attached, which passed quite through it. This 

 had manifestly belonged to a new generation of trees, growing above 

 the remains of others already in the state of casts in sand, but not 

 consolidated into stone. 



One of the beds of shale in the vicinity of a small coal seam at this 

 place, contains abundance of Naiadites, Cythcre, fish-scales and teeth, 

 and Coprolites, or the fossil excrement of fishes. A fragment of a large 

 Eurypterus, previously figured (Fig. 50) was also found here. 



Four miles to the north-east of Port Hood, the Lower Carboniferous 

 limestone and gypsum appear ; and this part of the system continues 

 to Mabou River, where it is very extensively developed. Tlie lime- 

 stone near this river has shells of Productus semireticulatus and abun- 

 dance of fragments of Encrinites ; and one of the beds has an Oolitic 

 structure, — that is, it is made up of small round grains, precisely like 

 small shot cemented togethei", or the roe of a fish. This peculiar 

 structure is supposed to have been produced by the calcareous matter 

 collecting itself around minute grains of sand or other bodies, and thus 

 taking the form of little concretionaiy balls, which were finally ce- 

 mented into rock. It was at one time supposed to be confined to a 



