390 
The Pewsey line, after passing through the valleys of Ham and 
Kingsclere, is traceable between Woolverton and Hannington, cn 
towards Monks Sherborne, and fades away at Old Basing, apparently 
without entering the tertiary beds of the London basin*. This 
meets in synclinal relation with a ne projected from the north- 
west corner of the Wolmar valley from Pease Marsh, near Guildford, - 
through Farnham and the high chalk range of Froyle, Shaldon, 
Dummer and Popham, and appears to fade away in the country 
west of Andover, where it is lost in the greater swell of the Burgh- 
clere Hills, and the more dominant power of the Pewsey upheaval. 
The anticlinal line of Wardour, left by Dr. Fitton (in his ‘ History 
of the Beds below the Chalk’+) at Harnham Hull, S. of Salisbury, 
Mr. Martin finds traceable eastward, north of Dean Hill, and east of 
the Avon, to the banks of the Test, where it dips under the tertiary 
beds between Michaelmarsh and Romsey, and appears to fade away 
between the above-mentioned river and the Itching. In synelinal 
relation this line is also met and passed by a very remarkable anti- 
clinal, traceable in strict approximation with, and by-and-by to be 
proved to be the prowimate cause of, the whole line of the South 
Down escarpment (with a small exception between Lewes and Poy- 
nings) from Beachy Head to East Meon. In the vicinity of this place, - 
at Langrish, it enters the chalk, passes through the anticlinal valley 
of Chilcomb near Winchester and that city, and is lost in the Bos- 
sington Hills, pointing towards, but not satisfactorily traced into, 
the Warminster Ime. 
The details of all three lines of elevation are made out in the 
Ordnance Map, and sections given of the most illustrative points < 
and Mr. Martin adds some observations respecting the entrance of 
the great central lme of elevation of the Weald into the chalk at 
Selborne, and its progress westward between the lines of Pease- 
marsh on the north, and of Greenhurst or the South Down on the 
south, till it fades away in the great plateau of Salisbury Plain. — 
The author concludes this paper with some reference to the sub- 
ject of transverse fractures in these several longitudinal fissures, and: 
the cross drainage, to which, like that of the Weald, he proposes to 
return, in extension and emendation of the disquisitions formerly — 
published by him, as above alluded to, and which will be adduced 
as illustrative of the strong probability, if they do not amount (i 
connexion with the phanomena of drift) to absolute proof, of the 
élose relation of the acts of upheaval and violent aqueous abrasion. 
This necessarily implies the belief that the date of these lines of 
disturbance is posterior to that of all the stratified beds of the south- 
east part of England, as maintained in the author’s former essays, 
* The author thinks, that although this line fades away as it enters the 
tertiary beds at Old Basing, it is probable that, after passing silently along 
the London basin, it is revived again in the Isle of Thanet, which is a 
chalk outlier, by protrusion; in the same way that the parallel line of 
Portsdown Hill, High-down, near Worthing, and the Seaford Cliff (figured 
by Dr. Mantell) does on the southern coast. 
+ Geol. Trans., second sevies, vol. iv. p. 244. ef seq. 
