11 



short time in searching for fossils, the party crossed the Wye at the adjacent ferry, 

 and then turning to the right, ascended to the summit of the luxuriantly wooded 

 limestone range known as Coldwell Rocks, and proceeded to the well-known 

 Symond's Yat (or gate). The magnificent view from this spot, which forms the 

 narrow neck of a lofty rocky promontory washed on three sides by the Wye, is 

 too well known to need more than a passing allusion, but in a geological aspect 

 the scene was particularly interesting. Standing on the limestone ridge which 

 forms the edge of the Forest of Dean, to the eastward the eye ranged over a wide 

 champaign of the Old Red Sandstone, bounded in the distance to the east by the 

 syenitic peaks of Malvern and the oolitic ridges of the Cotteswolds. To the south 

 stretched the coal measures of the Forest basin ; and thus, at one view, the eye 

 embraced strata of widely different dates. From the Old Red Sandstone in 

 which the highest type of animals was fish, and the only vertebrate fish were 

 of species allied to the shark, down through the long ages of the gradual 

 deposition of immense masses of limestone — the intervals of violent volcanic 

 action, when massa'* of molten matter were forced through the existing strata— the 

 long succession of forests which grew, were successively submerged and covered 

 with sand, the mass again elevated to become the soil of new forests, and again 

 plunged into the ocean depths and buried beneath sand and mud, to be there 

 converted into fuel for the use of mankind— the gradual formation, above the 

 Carboniferous strata, of the New Red Sandstone, the Lias, and the Oolite, with 

 their myriads of animals of higher types than any which had previously appeared 

 — all were epitomised to the eye by these salient points of the landscjvpe. 



Some time having been devoted to this fascinating spot, Mr. Strickland and 

 a number of the party proceeded southward along the roivd to Uoleford. On their 

 way, Mr. Strickland pointed out the millstone-grit rock, which forms the inner 

 edge of the coal basin. The party made their way to Christchurch, where they 

 visited several pits, receiving from Mr. Strickland much interesting and valuable 

 information in regard to the vegetable remains, which are so abundant in the 

 shales and coal seams. Fragments of Sigillaria, and other extinct vegetation, were 

 found by several of the party in the debris lying about the mouths of the pits. 

 Mr. Strickland notices the fact that scarcely any remains of air-breathing land 

 animals had been found in the coal measures ; a circumstance which was probably 

 . due to the great excess of carbonic acid in the atmosphere at that remote period. 

 The vegetation which then flourished being of genera, the analogues of which new 

 live chiefly in the torrid zone, it had been concluded that the heat of the earth in 

 the periods when these forests grew was very great ; and that circumstance, com- 

 bined with the excess of carbonic acid in the atmosphere, would cause a most 

 luxuriant growth of vegetation. Vegetables might be said to be constantly en- 

 gaged in producing carbon. From the atmosphere they drew it by decomposing the 

 carbonic acid ; and then, passing into the state of peat, and from peat to coal, they 

 became a depository of carbon. When the coal was drawn from the earth for the 

 use of man, part of the carbon passed off as carbonic acid gas into the atmosphere, 

 to be thence again drawn by plants, again stored up in the earth as coal, and 

 again liberated by combustion as before. The theory that these coal fields were 



