part 1] GATJLT Al^D LOWER GREENSAK^D NEAR LEIGHTOX. 67 



the eminences capped by smooth iron-pan, the bottom layers o£ 

 clay (4 a), for several inclies up, are sprinkled with coarse grit and 

 small pebbles ranging up to the size of peas, which denote the 

 continuance of current-action, less forceful indeed than during 

 the accumulation of the underlying Basement bed, but yet strong 

 enough to retard the sedimentation of clayey matter. Consequently 

 these few inches of gritty clay, usually quite unfossiliferous, may 

 represent a time-equivalent as long as, or longer than, that of the 

 10-ft. ' i?tterru^tus-hedi'' (Price's I) of Folkestone; and their 

 absence on the knoll-tops may indicate the lapse of the same period 

 without sedimentation. In the overl^dng gritless clays (4), the 

 presence of strings of undisturbed brown-coated phosphatic nodules 

 is still indicative of slow sedimentation, and the scantiness and 

 crushed condition of the fossils point the same way, as most organic 

 remains require quick burial for their preservation. So far as 

 the scanty fossil-evidence goes, these gritless clays probably repre- 

 sent, more or less imperfectly, Beds II to VI of Price's Folkestone 

 classification ; but it is hardly likely that all the Folkestone sub- 

 divisions can be separatelj^ distinguished in this condensed 

 sequence, just as it has been found impracticable in the similarly- 

 condensed sequence of the North of France. As in France, too, 

 ' Belemnites minimus ' is the most abundant fossil of the beds, and 

 is rare or absent in most of the Upper Gault. 



Besides this deficiency towards its base, the Lower Gault shows 

 also an arrest of development at its top, which must have had a 

 further effect in reducing its thickness, though at this horizon the 

 Folkestone section has suffered similarl}^, as Price has impressively 

 shown. 1^ The phosphatic nodule-bed exposed near the top of 

 Harris's pit (fig. 3, p. 7), and less clearly in evidence in other 

 sections, has its equivalent, as already shown (p. 9), at approxi- 

 mately the same horizon at Folkestone (Price's Bed VIII, 'the 

 Junction-bed'), where identical conditions are implied. It is likely 

 enough, however, that these conditions were not absolutely syn- 

 chronous in two spots so far apart, as their belt of impact probably 

 moved from place to place under the inflaence of the progressive 

 changes. The ' compound ' character of the nodules and the way in 

 which many have been abraded, and scarred by adherent organisms, 

 while others are comparatively intact, afford proof of original slow 

 deposition, of subsequent winnowing-away of the matrix, perhaps 

 more than once, and of time for the regrowth of concretionary 

 matter around the old nuclei. We are, in short, dealing with a 

 ' condensed deposit ' ; and the assemblage of fossils found elsewhere 

 at separate levels, first commented on by Jukes-Browne, ^ is thus 

 to be accounted for. The mixture appears to be somewhat greater 

 than at Folkestone, which may imply either an earlier beginning 

 and longer persistence of the conditions, or the winnowing-away 



^ ' The Gault ' op. supra cit. p. 9. 



^ 'The Gault & Upper Greensand ' Mem. Geol. Surv. 1900, pp. 275, 278, 

 235. 



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