MIDDLE CHALK—BEDFORDSHIRE. 
463 
Stratigraphical Details. 
Zone of Rhynchonella Cuvieri. 
Tring stands upon the chalk of this zone, but no good exposure 
of it was seen near this town. About two miles to the north¬ 
east, however, by the house called “ The Folly/’ a quarry shows 
its upper beds ; the highest bed is white and contains a layer 
of black flints, the next 9 feet consist of massive, slightly yellowish 
or cream-coloured chalk with many fragments of Inoceramus, 
while the lower 6 feet are beds of hard nodular chalk full of Inoce¬ 
ramus mytiloides and Rhynchonella Cuvieri. 
The lower part of the zone is exposed in a pit south of Ivinghoe 
and east of Pitstone. (See Fig. 43,) The section here in 1884 was : 
ft. in. 
Hard yellowish nodular chalk, with Inoceramus mytiloides 
and Rhynchonella Cuvieri ------ 
FTv/r ii (Very hard nodular rocky chalk, full of small 
■R V 1 nodules, in several beds - 
00 l Very hard yellowish nodular chalk 
(Layer of buff-coloured marl - 
Lower | Hard whitish chalk, passing into next - 
Chalk. 1 Greenish shaly marl, with Act. plenus 
iSofter dull white chalk, up to 
6 0 
6 0 
3 0 
0 6 
2 0 
0 2-4 
8 0 
About 26 0 
The beds are dipping at an angle of about 3° to the south east. 
The Melbourn Eock is also exposed in a pit three-quarters of a 
mile south-west of Eddlesborough church, and in another pit by 
the side of the road to Dagnal, one and a quarter mile south-east of 
Eddlesborough. 
The hard chalk of this zone forms the base of the plateau of 
Maiden Bower, west of Dunstable, and there are three small out¬ 
liers of Melbourn Eock between it and the great tumulus of Tot- 
ternhoe ; there are no open sections at present, but the large 
quarries at Totternhoe may be eventually cut back into the base 
of the Eock. 
The next good exposure of this rock is in the quarry by the 
side of the railway near Leagrave, north-west of Luton. This 
quarry has been mentioned on p. 191 ; the lowest bed of the 
Melbourn Eock is a massive bed 3 feet thick of very hard 
nodular chalk and the next 5 feet are nearly as hard, but form, 
thinner beds with marly partings. The rock is nearly white 
when quarried, but weathers to a creamy yellow tint. 
West of Streatley the Melbourn Eock and Rh. Cuvieri chalk form 
a fine and bold piece of country, running out into many pro¬ 
montories which are separated by deep and picturesque combes 
and valleys. It is evident that the hard rocky chalk has protected 
the softer lower chalk but has been itself trenched by the action 
of rain-streams flowing off the higher slopes of the escarpment. 
The rock is exposed in a pit three-quarters of a mile south-west 
