Ill 



THE GEOLOGIST. 



" "We stand nearly upon the summit of the protruded Silurian dome, re- 

 presented in a coloured section, published in the first edition of Murchi- 

 son's ' Silurian System,' and may find in abundance under our feet cha- 

 racteristic shells aud corals of thellpper Ludlow beds, though much damaged 

 by the action of the tidal waters. The colour of this rock differs so little 

 from that of the Old Hed Sandstone beds which once rested immediately 

 upon it, and still flank it, that the precise point of contact is difficult to 

 discover. 



"Upon the opposite shore, full in our view, are the Old Red Sandstone 

 rocks which form the upturned edges of the Forest of Dean coal-basin, 

 the equivalents of the cornstones, and show at a glance, by the well-marked 

 anticlinal lines of their strata, dipping from one point towards Lydney, and 

 from another towards Gloucester, the wave-like character of the motion of 

 the subjacent beds, by which their elevation, with that of the Silurian 

 rock just mentioned, was effected, and their curvatures produced. The 

 transverse section, showing how this last passes under the others, appears 

 to us to be of equal interest to the published section, and we have here ven- 

 tured to produce it, from such observations as the constantly-changing bed 

 of the river has enabled us to make ; remarking, that from the inaccessi- 

 bility of the former, the Club would confer a boon upon its members by re- 

 publishing it. 



" Walking along under the cliff towards the Berkeley Arms Inn, from 

 the seat in front of which the finest view of the district, to be seen from 

 the river, may be obtained, we arrive at the mass of Old Bed Sandstone, 

 anticlinal to that over which we have just passed, upon which the house 

 stands, although, from the amount of silt deposited within the last ten or 

 twelve years, the point of junction is obscured ; and crossing the road lead- 

 ing to the pier, we come at once to the Lias beds, which form the well- 

 known Purton section, reposing unconformably upon the same. Some 

 forty years since, the principal channel ran under this cliff; but, from the 

 operation of the breakwater commenced by the late Earl Fitzhardinge. 

 land is rapidly forming here, and the current has been diverted to the 

 Forest of Dean side. The alluvial deposit behind the breakwater, in the 

 direction of our course, from its yet unstable character, renders it difficult 

 to trace the Liassic beds from their immediate line of contact with the 

 Devonian ; but at the distance of about half a mile from the inn they be- 

 come accessible. . . . 



" Few scenes can more vividly impress themselves upon the mind of a 

 young geologist than that which presents itself here after a fall of the 

 rock, and its exposure for a few weeks to the tidal and atmospheric action. 

 The beach is sometimes strewn with fossils in the finest possible condition, 

 more especially as regards Gryphires, which are found of every type con- 

 ceivable within the limits of one species ; and that one only exists here, 

 the writer has endeavoured to prove in a former paper, now forming a part 

 of the Transactions of the Cotteswold Naturalists' Club. . . . (See no- 

 tice in a former volume of the ' Geologist.') 



" We have now arrived at the end of the cliff near the second break- 

 water. Higher up the vale of Gloucester, it is difficult to obtain a clear 

 idea of the correlation of the vast beds of gravel composed of the detritus 

 of the Liassic and Oolitic beds of the neighbouring hills, containing elephant 

 and hippopotamous remains, occasional chalk-flints, etc., with what is popu- 

 larly known as the Northern Drift (but to which appellation we conceive 

 that there are substantial reasons for objecting). Be that as it may, the 

 order of superpositiou is well shown in a small excavation within a few 

 yards of the breakwater upon the edge of the cliff, where a bed of the 

 gravel above-mentioned has been worked to a small extent. 



