Among the finest panoramic views may be mentioned:--
(2) From the village of Wigginton, looking S.
(3) From the high-road between Graveley and Baldock.
(4) From Windmill Hill, Hitchin, looking W.
There were medicinal waters at Barnet, Northaw, Hemel Hempstead and Welwyn, but these are now disused. Many other details touching physiographical characteristics are mentioned as occasion arises in the Alphabetical Gazetteer which follows this Introduction.
The Geology of Hertfordshire must be here summarised in few words. The predominant formations are the Cretaceous and the Tertiary.
CRETACEOUS.--Ignoring the Gault, which barely touches the county, this formation consists chiefly of Chalk-marl, Lower, Middle and Upper Chalk. A series of Chalk Downs, an extension of the Chiltern Hills, stretches, roughly speaking, from Tring to Royston, forming by far the most prominent natural feature of Hertfordshire. The oldest rocks are in the N.W.
_The Chalk Marl_ is superimposed upon the Gault and Upper Greensand beds, which are confined to the western portion of the county. Its upper layer passes into a sandy limestone, known as Totternhoe stone, which has furnished materials for many churches in the shire. Ashwell, Pirton and Tring may be named as neighbourhoods where this stratum may be traced.
_The Lower Chalk_ is devoid of flints, and rests, in somewhat steeply sloping beds, upon the Totternhoe stone. It forms the western slopes of the Dunstable Downs, and of the Chiltern Hills. It is fossiliferous, one of the commonest of its shells being the Terebratula.
_The Middle Chalk_, of resonant hardness, is laminated, and has at its base the Melbourn Rock and at its summit the Chalk Rock. Nodules of flint, greenish in appearance, and (rarely) arranged in layers, occur sparsely in the Middle Chalk, which may be traced in the neighbourhood of Boxmoor, Berkhampstead and Baldock, and also in a few other districts.
_The Upper Chalk._--Although, as has been stated, the configuration of Hertfordshire is very undulating, we are able to discern a general trend in certain districts. Thus, there is a gradual slope to the S. from the N.W. and central hills, a slope which comprises the larger part of the county. This slope is formed of the Upper Chalk, a formation abounding in layers of black flints. The chalk is whiter than that of the lower beds, and very much softer. Fossil sponges, sea-urchins, etc., are abundant in this formation.