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Richard Lydekker.

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We may now turn to the formations overlying the
Chalk in the southern half of the county. Here it should
be mentioned that all the formations hitherto described
overlie (or underlie) one another in what is termed con-
formable sequence; that is to say, there is no break
between them, but a more or less nearly complete passage
from one to another. Between the Chalk and the
overlying Tertiary formations, there is, on the other
hand, a great break or "unconformity"; the surface of
the Chalk having been worn into a very irregular contour,
above which we pass suddenly to the Tertiary beds,
generally containing at their base a number of rolled chalk
flints. This indicates that before the Tertiary beds were
laid down, the Chalk had become dry land ; after which
a portion of it once more subsided beneath the ocean.
The Tertiary beds are in fact formed for the most part
from the debris, or wearing away of the old Chalk land.

The lowest Tertiary stratum of eastern and southern
Hertfordshire is known as the Woolwich and Reading
beds. These consist of alternations of bright-coloured
plastic clays and sandy or pebble-beds ; their maximum
thickness in the county being about 35 feet. They form
a band extending from Harefield Park to Watford,
and thence to Hatfield and Hertford. Below the
Woolwich and Reading beds we come on the London
Clay, of which the basement bed contains a layer of flint



GEOLOGY AND SOIL 35

pebbles, although the remainder of this thick formation is
a stiff blue clay, turning brown when exposed to the
action of the weather. Originally these Tertiary forma-
tions must have extended all over the Chalk of central
Hertfordshire, as is demonstrated by the occurrence of
patches, or "outliers," of them over a zone of considerable
width. Such Tertiary outliers occur at Micklefield Hall,
Micklefield Green, Sarratt, Abbot's Langley, Bedmond,
Bennet's End, and Leverstock Green, and in the northern,
or St Peter's portion of St Albans.

Closely connected with these Tertiary formations is
the well-known Hertfordshire pudding-stone ; a con-
glomerate formed of stained flint-pebbles cemented together
by a flinty matrix as hard as the pebbles themselves, so
that a fracture forms a clean surface traversing both
pebbles and cement. This pudding-stone is usually found
in the gravels (or washed out of them) in irregular masses,
weighing from a few pounds to as many tons. It is
stated, however, to occur in its original bedding between
Aldenham and Shenley; and the rock evidently represents
a hardened zone of the Woolwich and Reading beds.
Pudding-stone is found in special abundance at St Albans
and again in the neighbourhood of Great Gaddesden.
In some St Albans specimens the pebbles are stained
black for a considerable thickness by the oxides of iron,
while the central core is bright red or orange. Such
specimens, when cut and polished, form ornamental
stones of great beauty ; but, on account of their hardness,
the expense of cutting is very heavy.

Except on the higher part of the Chalk Downs, and

3-2



36 HERTFORDSHIRE

very generally along a narrow band halfway up the sides
of the valleys, the aforesaid formations are but rarely
exposed in the county at the surface, on account of being
overlaid with superficial deposits of gravel, clay, etc.,
which are of post-Tertiary age, and were deposited for the
most part during the time that man has been an inhabitant
of the world. These superficial beds are very frequently
termed "drift," on account of a large portion being
formed by ice, at the time that northern Europe was
under the influence of the great glacial period. Over
most of the chalk area the denuded surface of the Chalk is
covered with a thick layer of stiff" clay full of flints, this
layer being formed by the disintegration of the Chalk
itself, the soluble calcareous portion being dissolved and
carried away, while the insoluble flints and clay remain.
Above this layer in the neighbourhood of Hertford,
Barnet, and elsewhere, is a series of gravelly beds assigned
to the middle division of the glacial period; while these in
turn are overlaid locally, as at Bricket Wood, between
St Albans and Watford, by the chalky Boulder-clay, of
upper glacial age, which is there some twenty feet in
thickness. In other places, as at Harpenden, the hills are
capped by a still greater thickness of clayey deposits,
mingled with flints, resting upon a very irregular surface
of Chalk, which appears to be for the most part of glacial
origin. Speaking generally, Boulder-clay is characteristic
of the east, and clay with flints and gravel of the western
side of the county.

Half way down the sides of the hills, in the district last
named, the Chalk is more or less completely exposed at the



GEOLOGY AND SOIL 37

surface along a narrow zone, below which we come upon
deposits of gravel, sand, and clay filling the bottoms of the
valleys. At Bowling Alley, Harpenden, these deposits are
fully forty feet in thickness. Although they have been
supposed to be the result of river action, it is more probable
that they are due to rain-wash. Indeed this is practically
proved in the case of the valley leading from Harpenden
towards No-Man's-Land, where the lower end is blocked
by a ridge of gravel, which could not possibly have been
formed by river action. The stones in these valley-
gravels are of irregular shape, and thus quite different
from the rounded pebbles of the gravels of the Woolwich
and Reading beds, as seen at St Peter's, St Albans. At
Harpenden the uppermost layer of valley-gravel is ex-
tremely clean and sharp, generally of a golden yellow
colour with blackish veins. Deposits of brick-earth occur
locally throughout the Chalk area.

Over the greater part of the county the soil is the
result of the decomposition of the foregoing superficial
formations ; and is consequently in most cases of a stiffer
and more clayey character on the hill-tops than in the
valleys, where it frequently forms only a bed of a foot, or
even less, in thickness above the sharp, running gravel.
Everywhere in the Chalk districts the soil contains a vast
number of flints ; but it is, nevertheless, admirably adapted
for corn-growing, and especially for malting-grain ;
Hertford being one of the four English counties best
suited to crops of the latter nature. On many of the
unenclosed commons the soil is, however, of a poor and
hungry nature, producing various kinds of inferior grass,



38 HERTFORDSHIRE

together with spring-flowering gorse, as on Harpenden
Common, or heather, as at Kingsbourn Green, between
Harpenden and Luton, and at Gustard Wood, near
Wheathampstead. On the higher Chalk Downs near
Dunstable and Royston there is little or no soil properly
so-called ; the short, but sweet and nourishing grass
growing on the chalk itself. A very different type of
soil obtains in the London Clay area in the south and east
of the county ; this being heavy and clayey, and thus
better suited for grass than for corn ; in fact in the old
days the Middlesex portion of this district was known to
the country people as the " Hay-country." Along many
of the river-valleys peaty soils of a marshy and swampy
nature prevail.



7. Natural History.

In former days, when the mammoth or hairy elephant,
the extinct woolly rhinoceros, and the wild ox, together
with the African hippopotamus and spotted hyaena roamed
over the Thames valley and afforded sport to our pre-
historic ancestors, England was joined to the Continent
across what is now the English Channel j so that the
animals and plants of the southern portion of our islands,
at any rate, were more or less nearly identical with those
of France and Belgium. The advent of the great ice
age, or glacial period, caused, however, a vast disturbance
of the fauna and flora (as the assemblages of animals and
plants characteristic of different countries are respectively



NATURAL HISTORY



39



termed), especially as about this time there occurred
several oscillations in the level of our country, during one
or more of which Great Britain was temporarily separated
from the Continent. How much or how little these and
other changes had to do with the poverty of the British
fauna as compared with that of the Continent is too long
and difficult a question to be discussed in this place ; but




Six Hills, Stevenage (Danish Barrows)

certain it is that even the southern counties of England
do possess fewer species of animals and plants than France
or Belgium ; that this poverty increases with the distance
from the Continent ; and that Ireland is much poorer in
species than England. It may perhaps be well to add,
although it does not really concern our subject, that there
appears to have been another land-connection by means



40 HERTFORDSHIRE

of which Scotland and Ireland received a portion of their
faunas from Scandinavia by way of what is now the
North Sea.

At the date of the final insulation of Great Britain
from the Continent there is every reason to believe that
all the land animals of the former were identical with
species inhabiting adjacent regions of the latter. And
even at the present day, when isolation has for centuries
been exerting its influence on the non-migratory (and in
some degree also on the migratory) animals, there are no
species of quadrupeds (mammals), birds, or reptiles abso-
lutely peculiar to our islands, with the exception of the
grouse ; and in the opinion of many naturalists that bird
should be regarded rather as a local variety or race of the
willow-grouse of Scandinavia than as a distinct species.

Minor variations, however, characterise many, if not
indeed all, of our British quadrupeds and birds when
contrasted with their continental representatives. The
British squirrel is, for instance, very markedly distinct
from all the continental races of that animal in the matter
of colouring, while somewhat less decided differences
characterise our badger, hare, field-mice, etc. Similarly,
among birds, the British coal-tit is so decidedly distinct
from its continental representatives that it is regarded by
some naturalists as entitled to rank as a species by itself;
and minor differences from their continental cousins are
displayed by the British redbreast, bullfinch, great titmouse,
and many other resident species. Indeed, if careful com-
parisons were instituted between sufficiently large series of
specimens, it is almost certain that all species of resident



NATURAL HISTORY 41

British land animals, as well as exclusively fresh-water
fishes, would display certain differences from their foreign
representatives ; while in some instances, at any rate, as is
already known to be the case in regard to certain species,
more than one local race of an animal may exist in our
own islands.

It is, however, a question as to what is to be gained
by the recognition of such comparatively trifling local
differences in animals (and still'more by assigning to them
distinct technical names), as the splitting process may be
carried to an almost endless degree. A large London
fishmonger is, for instance (as the writer is informed),
able to distinguish a Tay from a Severn or Avon salmon;
while a wholesale game-dealer will in like manner dis-
criminate between a Perthshire and a Yorkshire grouse.
In like manner a Hertfordshire badger or stoat may be
distinguished from their Midland or North of England
representatives ; but it is difficult to see in what respect
we should be the better for the recognising of the existence
of such differences.

Accordingly, the fauna and flora of Hertfordshire may
be regarded for all practical purposes as more or less com-
pletely identical with that of the south-east of England
generally ; and nothing would be gained, even if space
permitted, by giving lists of the species which have been
found within the limits of our county.

The fauna and flora of Hertfordshire, like those of
other counties with varying geological formations, are not,
however, by any means the same everywhere. On the
contrary, there are well-marked local differences mainly



42 HERTFORDSHIRE

associated with what naturalists call "station"; that is
to say, differences of elevation, soil, geological formation,
climate, etc., etc. The animals and plants of the high chalk
downs in the neighbourhood of Gaddesden, Dunstable,
and Ashwell, are for instance more or less markedly
distinct from those of the lower level corn-growing areas
of the centre of the county. On these elevated tracts we
find, for example, wheatears, stone-curlews (near Tring),
blue butterflies, burnet-moths, small brown-banded white
snails, a periwinkle-like snail with a horny door to its
shell known as Cyclostoma, blue gentians, certain orchids,
and many other kinds of plants rarely or never seen on
the low grounds. The open commons and heaths, on
the other hand, as has been already mentioned, are the
home of heather and gorse, together with various distinc-
tive birds and reptiles, such as stonechats, whinchats,
titlarks, goldfinches, vipers, slow-worms, and lizards. In
the river-bottoms and other swampy localities we find
marsh and water-birds, such as yellow wagtails, snipes,
sandpipers, grebes (at Tring), herons, moorhens, water-
rails, coots, dabchicks, and wild duck, together with
(locally) the common grass or water snake, amber-snails,
marsh-marigolds, purple loose-strife, ragged robin, reeds,
and yellow flags.

Beech trees, as mentioned above, form the predominant
timber on the chalk-lands other than the high downs,
while on the heavier soils of the centre of the county
their place is mainly taken by elm and ash. On these
lowlands and other open cultivated tracts are found such
birds as partridges, corncrakes, lapwings, pipits, and larks ;



NATURAL HISTORY 43

while in the coppices, hedgerows, and gardens we look
for nightingales (from which bird Harpenden takes its
name, haerpen being a nightingale and dene a valley in
Anglo-Saxon), blackcaps, whitethroats, wrens, and nut-
hatches ; while the woods are the resort of green and
spotted woodpeckers, wood-pigeons, jays, and pheasants.
The low grass-growing clay-plains on the southern side
of the county support, as already stated, an abundant
growth of oaks to the almost complete exclusion of other
timber trees ; and this area doubtless also presents certain
peculiarities in its fauna distinguishing it from the corn-
growing tract to the north. The oaks grow to a very
great size, especially at Sacombe and Woodhall Park,
and three notable specimens in the county are Queen
Elizabeth's oak at Hatfield, Goff's oak at Cheshunt,
and the Panshanger oak.

In addition to these local peculiarities in the fauna
dependent upon elevation, geological formation, soil, and
the presence or absence of forest, there are, however,
certain others for which climate may possibly account.

A case in point is afforded by the distribution of stag-
beetles and magpies in the county. Both these species are
unknown in the district immediately round Harpenden,
while the former, at any rate, are likewise unknown in
the St Albans district, and apparently between that city
and London. If, however, we travel from Harpenden to
the east, magpies may be met with when we reach
Codicote, while in the opposite direction they occur in
the Hemel Hempstead district. As to the exact point
where stag-beetles make their appearance in the latter



44 HERTFORDSHIRE

direction the writer has no information, but they are to
be met with in the neighbourhood of Rickmansworth and
elsewhere on the Buckinghamshire border, and become
quite common in that county. Grass-snakes, so far as the
writer is aware, are likewise absent from the Harpenden
neighbourhood, although on the Cambridgeshire side of
the county they are quite common, as they are across the
border.

If the local distribution of these species were carefully
worked out and mapped, we might perhaps be able to
account for what is at present a puzzle.

With the increase of population and building the wild
fauna of Hertfordshire, like that of England generally,
has been gradually becoming poorer in species probably
indeed from the time the mammoth and the woolly
rhinoceros were exterminated, as they possibly were, by
our prehistoric ancestors. When the wolf, the bear, the
wild cat, and the beaver disappeared, is quite unknown ;
but it is in comparatively modern times that the marten
has been exterminated, a solitary individual of this species
having been killed in the county within a score of miles
of London, that is to say near Watford, so recently as
December, 1872. Polecats appear to have almost if not
quite disappeared from the county, although a straggler
may occasionally enter from Buckinghamshire, where a
few still survive ; and one was trapped in Ware Park
about 1885. Otters are rare, although a few occasionally
appear in the lower part of the Lea valley, and some
may enter the county from Buckinghamshire, in parts of
which they are much more common, the Buckinghamshire



NATURAL HISTORY 45

Otter-hounds having killed over a score of these animals
in 1908. Some years ago badgers were to be found in
many parts of the county, a well-known haunt previous
to 1840 being "Badger's Dell" in Cassiobury Park.
They still occur locally in certain parts of the Bucking-
hamshire side of the county, and probably elsewhere.
Foxes owe their preservation mainly to the sporting
instincts of the county gentry and farmers.

Among birds that have disappeared from the county,
the most to be regretted is the bustard, which in the
early part of last century was still to be found in the
neighbourhood of Royston, although the precise date of
its extermination from this part of England is unknown.
The bittern, too, is, at the very most, known only as an
occasional straggler ; but a specimen was shot in a small
marshy pond on Harpenden Common some time previous
to 1860. The Royston crow, by some naturalists held
to be only a form of the common crow, has been named
from the Hertfordshire town, though a widespread species
throughout many parts of Europe.

Neither has extermination been confined to animals.
Fern-hunters have in some instances made a clean sweep
of certain species of ferns from many districts, if not from
the county generally ; and nowadays aspleniums, shield-
ferns, polypodies, and false maidenhair (trichomanes) have
completely disappeared from the Harpenden high roads
and lanes; the present writer possessing in his garden
what he believes to be the sole remaining indigenous
specimen of the last-named species.

Among localities specially celebrated for birds in the



46



HERTFORDSHIRE



county are Tring reservoirs, where vast flocks of water-
birds congregate, especially in winter. Here breeds the
great crested grebe ; and here, too, was shot in 1901 the
only known British example of the white-eyed pochard.
The neighbouring downs, as already mentioned, form one




of the chief English resorts of the stone-curlew, or thick-
knee ; a species of especial interest on account of the
remarkable manner in which both birds and eggs assimilate
to their surroundings.



NATURAL HISTORY 47

Rare birds, as well as various maritime species driven
from their normal resorts by stress of weather, make their
appearance occasionally in various parts of the county, but
references to very few of such cases must suffice. During
the great visitation of sand-grouse (a bird normally charac-
teristic of the steppes of Central Asia) to the British
Isles in 1863, some individuals reached this county. In
the early part of last century a little auk, or rotche, was
taken on the millhead at Wheathampstead during very
severe weather; a great northern diver has been seen on
Tring reservoir ; a pair of storm petrels were killed some
five-and-twenty years ago at Hemel Hempstead, where
snow-buntings have likewise been seen ; while various
species of gulls from time to time put in an appearance in
winter. Among recent events of this nature the appear-
ance at Harpenden of an immature specimen of the great
purple heron is certainly noteworthy. In 1878 the late
Mr J. E. Littleboy had recorded 201 species of birds
from the county, and a few others have been added since,
bringing up the number to 2IO in 1902.

In regard to fishes, it is of interest to quote the
following passage from Sir Henry Chauncy's Historical
Antiquities of Hertfordshire^ published early in the
eighteenth century. After referring to its other fish, it is
there stated, in the author's quaint language, that the river
Lea also contains "some Salmons; which (like young
Deer) have several denominations: the first Year they are
called Salmon-smelts, the second Year Salmon-sprats, the
third Year Salmon-forktails, the fourth Year Salmon-peall,
the fifth Year Salmonets, and the sixth Year Salmon ; and



48 HERTFORDSHIRE

if these Fish had free Passage by the Mills, and thro' the
Sluices at Waltham up the Stream towards Ware and
Hertford, where they might Spawn in fresh Water and
were carefully preserved from Pochers, they would greatly
increase in that River, and be of great benefit, as well to
the City of London as the Country ; for some Water-men
have observed, that they delight in this Stream, and play
much about those Sluices at Waltham."

Chauncy likewise mentions that trout from the Lea
below Hertford, where it has peaty banks, are much less
red than those from the gravelly streams of the chalk
districts.

For botanical purposes the county has been divided
into six districts corresponding to the river-basins ; the
first two belonging to the Ouse system, and comprising
the Cam and the Ivel basins, and the other four, com-
prising the Thame, the Colne, the Brent, and the Lea,
pertaining to the Thames system. Of these the Lea area
is the largest, the Colne next in size, the Ivel considerably
smaller, and the other three quite small. In some respects
the local characters of the flora are, however, better brought
out by taking the geological formations as a basis of
division. The Upper Chalk area, capped with much
Boulder-clay on the eastern, and with clay-and-flints and
gravel on the western side, corresponds very closely as
regards these divisions with the Lea and the Colne basins.
The Middle Chalk, which as we have seen' is exposed
on the flanks of the continuation of the Chiltern Hills in
the north-west, is peculiar in being the only area in the
county in which grows the pasque-flower, or anemone ;



NATURAL HISTORY 49

this chiefly flourishing on south-westerly slopes, as at
Aldbury Towers, near Tring. The Middle Chalk is
also the chief home of the various kinds of orchis ; the
dwarf, the man, and the butterfly orchis being apparently
restricted to this formation. The Tertiary area has a
vegetation of a totally different type from the so-called
" dry-plant type " characteristic of the Chalk area, but it
cannot be further mentioned here.

In the five adjacent counties there occur no species
of flowering plants unknown in Hertfordshire. On the
other hand, Hertfordshire has about a dozen plants (ex-
clusive of varieties of the bramble) unknown in the
adjacent counties. Of the 893 native flowering plants of
Hertfordshire about no have not been recorded from
Cambridgeshire, while about 1 20 are wanting in Bedford-
shire, 170 in Buckinghamshire, 140 in Middlesex, and
100 in Essex. These figures may, however, be subject
to considerable modification by future research. The
following passage on the relations of the Hertfordshire
flora is quoted from the Victoria History of the Counties
of England :

"Taking the number of species in any adjoining
county which are absent from Hertfordshire as the best
index of the degree of relationship, it would appear that
the flora of Bucks is the most nearly allied to that of
Herts, and that those of Cambridge and Essex aie the

most divergent This is just what .might be expected

from the physical features and geological structure of these
counties. The floras of Cambridge and Essex have also
a more northern or north-eastern facies [character] than

L. H. 4



50 HERTFORDSHIRE

that of Hertfordshire, which is of a decidedly southern
type. The large number of Hertfordshire species which
have not yet been recorded from Buckinghamshire is
probably due to the flora of that county not having been
so thoroughly investigated as ours has been."



8. Climate and Rainfall.

In its original sense the word climate meant the
degree of inclination of the sun's rays at any particular
spot at a specified date; but nowadays it is employed to


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