between Chrisichurch Head, Hampshire, and Studland Bay, Dorsetshire. 281 



centage of iron in some of these concretionary masses; and as exportation from 

 hence by water must always have been easy, it is probable that the ore used 

 in the ancient iron-works of the Mine Way, at the eastern extremity of 

 Hordwell Chff, near Muddiford, was procured from this part of the cHff. On 

 the summit of this promontory of Christchurch Head, are pits, from whence 

 ironstone has been extracted in former times, but perhaps for the purpose of 

 building" ; for some of the late repairs of the church at Christchurch have 

 shown that these concretions were used in filling up the foundations. This 

 series of strata of sand, loam and ferruginous concretions, is more than 20 feet 

 in thickness where it first rises at the East Point of Christchurch Head ; and, 

 before its outcrop about three quarters of a mile beyond the West Point, it 

 attains, in parts, the thickness of 50 feet. The apparent dip of the strata 

 in the cliffs is to the East; but the real dip may differ from this, as tranverse 

 sections cannot be obtained. The cliffs of this promontory and to the west of 

 it at the outcrop of the above strata, vary in height from about 40 to above 70 

 feet. The next bed that rises is a black bituminous clay with lignite (PI. XXX. 

 No. 1. d.), which is about 12 feet in thickness, and rests on a layer of round 

 black flints. The lignite with which the beach at the West Point is strewed, 

 is probably washed from this bed. Below this, a bed of reddish brown cho- 

 colate-coloured sand rises (PI. XXX. No. 1. e.), inclosing occasional flint 

 pebbles, about four feet thick and resting on a layer of small flint pebbles. 

 Below this is a bed of coal-black bituminous matter, varying from three to four 

 feet in thickness. (PI. XXX. No. 1. f.) Then a stratum of reddish brown sand 

 rises five feet thick. (PI. XXX. No. 1. g.) The variety and contrast of the 

 colours of the above strata remind the geologist of the section of Alum Bay. 

 These beds cannot easily be traced far, as they vary in colour rapidly and pass 

 into each other. The bituminous beds in particular, from containing less vege- 

 table matter in parts, change suddenly their appearance. The cliffs become 

 low after the outcro]) of these strata, as will be seen by the section, till near a 

 place called Double Ditches *, about three miles from Muddiford, the cliff 

 is only 17 feet in height. Here 12 feet of diluvium is seen at the top, and 

 below it five feet of white sand. (PI. XXX. No. 1. g.) 



At Double Ditches the cliff is about 15 feet high, entirely composed of 

 diluvium covered with blown sand. The cliff continues very low for a mile 



* Double Ditches is perhaps a corruption of Double Dikes ; for there is an entrenchment here 

 stretching across the low neck of land that connects Christchurch or Hengistbury Head with the 

 main land. This Head has been a defensive position in ancient times, and the old name Hengist- 

 bury seems to denote a Saxon origin. There is only one trench, now filled with blown sand, and 

 an agger on each side, which were no doubt provincially termed "dikes." 



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