half of the county. Here it should be mentioned that all the formations
hitherto described overlie (or underlie) one another in what is termed
conformable 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 _débris_, 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 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 formations 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 conglomerate 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 very generally along
a narrow band half way 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 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 extremely 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, 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 prehistoric ancestors, England was joined to the Continent across
what is now the English Channel; 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 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 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 of which Scotland and Ireland received a
portion of their faunas from Scandinavia by way of what is now the
North Sea.
[Illustration: Six Hills, Stevenage (Danish Barrows)]
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 absolutely 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 comparisons were
instituted between sufficiently large series of specimens, it is almost
certain that all species of resident 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 discriminate 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 completely 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 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 distinctive 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; 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 nuthatches; 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 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 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 Buckinghamshire 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 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.
[Illustration: Tring Park]
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 characteristic 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
appearance 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 210 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 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,
comprising 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; 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 110 species of flowering
plants unknown in Hertfordshire. On the other hand, Hertfordshire has
about a dozen plants (exclusive of varieties of the bramble) unknown
in the adjacent counties. Of the 893 native flowering plants of
Hertfordshire about 110 have not been recorded from Cambridgeshire,
while about 120 are wanting in Bedfordshire, 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 are 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 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.