28 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 2, 



impure coal containing trees with attached Spirorbis, and intermixed 

 with these fish-scales and Cypris, the whole being capped by Modiola- 

 shale. To account for the fossils in this coal, which rests on a true 

 underclay, we must suppose the submergence of a forest, in such 

 circumstances that fish and Cypris lived among its sunken trunks, 

 and were buried along with them as they decayed and fell to the 

 bottom. 



In Group XXIV. the waters retain their dominion, though gra- 

 dually filling up with sediment. The sandstones of this group are 

 very uniform and evenly bedded as compared with those of the last, 

 and present no indications of vicinity to shores or water-courses, 

 except in the presence of drift-wood and some singular scratches and 

 furrows on the surfaces of the shales, casts of which have been taken 

 by the overlying sandstones. Marks of this kind are very frequent 

 in the Coal formation. They occur on a grand scale in the sandstone 

 quarries of Pictou, and also on the French River of Tatmagouche. 

 Many of them might easily be included in the convenient tribe of 

 Fucoides, but their want of uniformity, the absence of organic 

 matter, and their occurrence in beds containing drift-trees render it 

 probable that they are scratches produced by roots or branches borne 

 over the surface by currents. Such marks in modern inundated 

 flats are usually straight, like glacial strise, but when stumps or 

 tree-tops are grounded and afterwards borne oflf, the most fantastic 

 markings are produced. Very singular appearances also result from 

 the eddying of the water around such obstacles, and much resemble 

 many of these markings on the carboniferous rocks. 



The XXVth Group is another series of fossil soils and their 

 accompaniments, terminating upward in a thick bituminous Umestone 

 and Modiola-shale, with their usual fossils. 



Group XXVI. — In the succeeding group we have the filling up of 

 the waters inhabited by Modiola, with mechanical detritus. One 

 erect tree occurs in this group, and many of the beds of sandstone 

 are ripple-marked. On one of these rippled sandstones I found, on 

 revisiting the section in 1853, a series of footprints, probably of some 

 reptilian quadruped allied to those found in the fossil tree in another 

 part of the section. These footprints are three-toed, each about 

 9 lines in length. The length of stride is 3^ inches, and the two 

 rows of footprints 3 inches apart. Just where the rows of steps bend 

 to the left, a slight mark nearer the left side appears to indicate a tail 

 (fig. 18, MS.). 



Group XXVII. is a dense series of uuderclays and their accom- 

 paniments, including eleven terrestrial or soil surfaces, five thin coals, 

 erect plants at four levels, and two bituminous limestones. It much 

 resembles some of the groups at the commencement of the section, 

 and like some of these is very pyritous, marking the action of sea- 

 water to a greater degree than in those central parts of the measures 

 where Modiolce and their accompaniments are less plentiful. The 

 most remarkable part of this group is that represented in fig. 8. 

 It includes a bed of erect Calami tes and an erect tree with distinct 

 Stigmaria-roots (fig. 12, ms.). The underclays are here so crowded 



