74 Geological Society : Mr. Lyell on the 



surface had converted a lake into an estuary, and subsequently into 

 a marine bay. But notwithstanding the natural connexion be- 

 tween the Wealden and the lower greensand, it does not follow that 

 the two formations ought to be merged in one system or natural 

 series. Dr. Mantell as long ago as 1822 pointed out the analogy 

 between the animals of the Wealden and those of the Stonesfield 

 beds ; and more recently Professor Owen has carried it out much 

 further. Professor Agassiz has pronounced the Ichthyolites of the 

 cretaceous system to be entirely dissimilar from those of the Wealden. 



Mr. Murchison inquires, where are we to draw the line of sepa- 

 ration which shall indicate precisely in our own country the base of 

 the Neocomian of foreign geologists, or in other words, the base of 

 the great continental cretaceous system ? On this point he remarks 

 that some small amount of compromise may eventually be found de- 

 sirable ; for whilst we have on the one hand full right to infer that 

 the larger portion of the Wealden must be classed in the oolitic 

 series, further inquiry may convince us that its uppermost part is of 

 the same age as the lowest Neocomian strata ; and thus we may 

 connect that portion of it with the cretaceous system. In the mean 

 time it is quite clear that a great part of the Neocomian is absolutely 

 the lower greensand itself. This view is confirmed by Count Key- 

 serling, who has identified fossils from the Neocomian strata of Kys- 

 lavodsk in the Caucasus, with specimens collected by him in com- 

 pany with Mr. Murchison in the lower greensand of the Isle of Wight. 



April 26. — A paper was read " On the upright Fossil-trees found 

 at different levels in the Coal strata of Cumberland, Nova Scotia." 

 By Charles Lyell, Esq., F.G.S. &c. 



The first notice of these fossil trees was published in 1829 by 

 Mr. Richard Brown, in Hali burton's ' Nova Scotia,' at which time 

 the erect trunks are described as extending through one bed of 

 sandstone, twelve feet thick. Their fossilization was attributed by 

 Mr. Brown to the inundation of the ground on which the forest 

 stood. Mr. Lyell in 1842 saw similar upright trees at more than 

 ten different levels, all placed at right angles to the planes of stratifi- 

 cation, which are inclined at an angle of 24° to the S.S.W. The 

 fossil trees extend over a space of from two to three miles from north 

 to south, and, acccording to Dr. Gesner, to more than twice that 

 distance from east to west. The containing strata resemble litho- 

 logically the English coal-measures, being composed of white and 

 brown sandstones, bituminous shales, and clay with ironstone. There 

 are about nineteen seams of coal, the most considerable being four feet 

 thick. The place where these are. best seen is called the South 

 Joggins, where the cliffs are from 150 to 200 feet high, forming the 

 southern shore of a branch of the Bay of Fundy, called Chignecto 

 Bay. The action of the tides, which rise sixty feet, exposes con- 

 tinually a fresh section, and every year different sets of trees are 

 seen in the face of the cliffs. 



The beds with which the coal and erect trees arc associated are 



* Abstracts of other papers by Mr. Lyell on the Geology of North 

 Am erica will be found in the preceding volume, p. 180. 



