484 Geological Society : — 



The author first described the general features of the north- 

 eastern portion of Essex, with its table-lands of gravel, clay valleys, 

 and tidal rivers. The present configuration of the district cannot be 

 due, in the author's opinion, to the action of such causes as we see 

 now in operation on the coast, combined with a slow elevation of the 

 land. As a rule, the sea-waves cannot excavate long narrow inlets 

 in horizontal and homogeneous beds, such as the gravel and clay of 

 the district under notice, but give rise to long, approximately straight 

 lines of cliff. The rounded sides of the Essex valleys seem to show 

 they were not formed by wave-action ; nor are there any evidences 

 of shingle-beds at the foot of the hills. Mr. Fisher believes that 

 the surface of this district, and that of many other districts composed 

 of yielding strata, must have been formed by a superincumbent 

 mass of water draining off from a flat or slightly dome-shaped area. 

 Slight depressions, cracks, or lines of readily yielding materials would 

 determine the drainage-streams as the water retreated ; and these 

 channels would be more or less scoured out according to the velo- 

 city of the water. Where the gravel covering of such a district was 

 cut through, the clay beneath would be channelled with a narrower 

 valley ; and where the gravel was wholly removed, the valleys would 

 be wider and the intermediate high ground rounded instead of being 

 flat-topped, just as is presented in those parts of the district where 

 the clay composes the surface. Similar appearances may be seen 

 on a small scale in the mud of a tidal river. Tidal action, however, 

 is not, according to the author, calculated to excavate narrow valleys 

 in horizontal beds. 



Mr. Fisher suggests that the land must have been elevated by a 

 sudden movement sufficient to have caused a rush of water from the 

 raised portions to seek a lower level, — either the land being raised 

 high and dry at once, or the sea-bottom raised to a higher level, 

 though still remaining beneath water. Such an elevation might be 

 repeated again and again, with intervals of submergence ; and such 

 conditions appear to have obtained in Norfolk as well as in Essex. 



The author states that, in his opinion, escarpments, such as are so 

 common among the secondary and tertiary beds, are rarely old cliffs, 

 and their often rounded forms must be due to agencies similar to 

 those which have produced the valleys of Essex. In some deep 

 gorges of the Chalk near Dorchester the author has seen flints and 

 great blocks of Tertiary puddingstone so arranged as to leave little 

 doubt of their having been left by violent currents of water. The 

 position of the Marlborough " Wethers " is also attributed by the 

 author to torrential action. 



Brick-earth is in part referred by Mr. Fisher to the deposition of 

 sediment from turbid waters ; but also in great part to the unlading 

 of icebergs. 



With regard to the manner in which the uprising of the land, 

 which brought about these aqueous cataclysms, has been effected — 

 whether by one slow and continued movement, or by one or more 

 sudden movements, or by a mixed succession of these, the author 

 argued that a slow and gradual elevation is not in accordance with 

 the contour of the existing surface of our softer strata ; that the ele- 



