'\x\ \J/}^ Lomlon and Hampshire Basins. 133 



side of the-long chalk triangle bounded by the Wiley and Nadder, 

 and the southern limb of the Warminster anticlinal line doing 

 the same for the north side_, a synclinal trough is Joi'med iix 

 which I suspect there are relics of tertiary beds. iHt i\%^ ^\oiU9 

 Of the valleys themselves, a stricter examination w>uld pro*-- 

 bably show that groups of fissures, puckerings, or subordinate 

 contortions, accompany the great central upheaval. That these 

 ph?enomena exist in greater force in the Weald Valley is most 

 probably owing to the great thickness of the Wealden formation. 

 If a section of the whole Wealden in this great exposure could 

 be obtained, it would exhibit the appearances we observe in somjB? 

 ancient schistose formations, and which obtain most probably in 

 argillaceous deposits of all ages (except the most recent) that 

 £t^rd the requisite thickness. 



j .Of the epoch of these parallel lines. of disruption, and of thaii?? 

 contemporaneity, I propose to treat when the phsenomena of 

 transverse fissure, drainage, lacerated escarpments, drift, and 

 other circumstances bearing on the subject of denudation come 

 to be. considered. Por the present it is sufficient to observe, that 

 the presence of tertiary beds of the Eocene period in great force 

 in some parts of the synclinal lines here reviewed, as, for instance, 

 in that of Salisbury, and the protrusion of the chalk through 

 them in the anticlinal, bespeak a date posterior to the sera of 

 those deposits. Of this, stronger evidence is yet to be adduced 

 from districts of similar structure not now imder review ; as, for 

 instance^ in the case of Portsdown and its synclinal line of the 

 Forest of Bere*. Indeed the proposition with which I started,, 

 the contemporaneity of the acts of elevation and denudation, ne- 

 cessarily implies an epoch posterior to all the regularly stratified 

 ^^^ %^ districts. ^^j ,^^^^ ^^^^ y^md^^iHA ^o 



jfl^ ni hii.F ^ ■ ■ ■ ■ — I t - rrfnv tu-o't vrnrmlff'). '-^jfi v; ■<n»d 



*T!'%^aVy 'Already pointed out the obvious connexion of the loii^'^ 

 line of the Greenhurst elevation wdth the escarpment of the 

 South Downs. And I may briefly call attention to the variable 

 force of these longitudinal fractures in the different parts *of > 

 their course. This is a matter of great importance as bearing. 

 oil the subject of transverse fissure. I have already spoken of 

 it in the Pewsey line. At one point it scarcely heaves the ter-^^ 

 tiarybeds; at another it is carried on in the chalk; and in; ^''^ 

 third it brings up the greensand on a level with the plastic clay. 

 In the Peasemarsh line we have seen that the Weald clay rises; ' 

 allowing something for denudation, within a few feet of the chalk 

 marl at Alton, and a transverse fissure shows itself at the point 



* See also Dr. Buckland's raemoii* on " Valleys of Elevation," Geol. 

 Trans., vol. n. 2nd series, p. 125. ^ ^^^^, ^,^.,, a 



PhU. Mag. S. 4. Vol. 3. No. 9. Aug. 1851. ""'^ "-""fi-"™"'' 



