Mike Howgate

London has a number of rivers flowing into the Thames both north and south of the river, though this presentation dealt only with those north of the Thames and focussed on the Wlbrook, the Fleet and the Tyburn.  While the headwaters are often still above ground, in the suburbs, the City and Westminster, they are culverted and hidden.  As early as 1598, John Stow described the Walbrook as already covered and hidden.  A good book on the subject is N.J. Barton – Lost rivers of London.

Map showing the lost rivers of London

Many of the rivers can be traced.  The London Topographic Society has published the Agas map and the Copperplate map showing Elizabethan rivers.  Street names such as Cow Cross, Town Mill, Fleet Street, Knightsbridge tell of hidden rivers, as do early Ordnance Survey maps before the major development of London and its suburbs.  One of the best sources is the North London Geological Survey map, where old river courses are picked out in alluvium.

There is also City mythology, such as the reputed stream under the Bank of England used by bank robbers to enter via the Walbrook culvert.  However, this is a myth.

Subsidence also occurs due to lack of maintenance of the culverts.  The Walbrook in the City of London runs alongside Mansion House and St Stephens Walbrook has huge cracks in the wall.  These were underpinned by Sir Peter Palumbo when building No. 1 Poultry.  The church was slipping into the Walbrook valley because it was founded partly on London clay and with the tower on alluvium. 

Sewers in London came into the public eye with the book The great stink describing the work of Joseph Bazalgette, whose interception sewers intercepted all the rivers and use part of their flow to flush the system.

River Walbrook

The Walbrook probably starts on the fringes of Hackney, from springs at the base of the Hackney Gravels.  The Roman riverfront was 60m back from the current riverfront and the Wlbrook approaches from Moorgate Circus and Spitalfields.  In 1570, Moorfield, north of Moorgate, was open ground used for drying laundry etc.  The Walbrook drains into the City Ditch (alongside the City wall) at All Hallows on the Wall.  The Wlbrook had a water mill (probably an undershot mill with a 2-3 feet drop).  In the 18^th century a culvert was excavated with iron grilles at either end.  The City Ditch runs from Moorgate through Bishopsgate and Aldgate to the Tower of London.

At St Margaret’s Lothbury, one corner of the church is collapsing into a Walbrook culvert and St Mildred Poultry is no longer there but a substantial stream was described as going through it in 1860. At Walbrook, the street, excavations in 1956 discovered the Temple of Mithras, which was previously unknown, though Mithraian artefacts had been found in Victorian excavations for building foundations.  The bust of Mithra was found on the day before the builders were due to move in and a 12-month stay of execution was granted for proper excavation.  The Temple was moved to its present location about 200 feet away and it is now 10 feet above the surface when it was previously 20 feet below it.  The Walbrook runs along Canon Street to the low-level northern interceptor sewer.

River Holborn (or Fleet)

This river has at least 4 names, the Holborn, the Fleet, the Turnmill Brook and the River of Wells.  While the name Fleet has tended to stick, it should properly only refer to the tidal inlet (as far upstream as Holborn Viaduct).  It is not on Fleet Street, which is the road leading to the River Fleet, just as Holborn is the road leading to the River Holborn. 

Its source is on Hampstead Heath and Highgate, which is the source of a number of rrivers, such as the Westbourne Tyburn and Fleet draining south, tributaries of the River Brent draining north and Hackney Brook and Mosul Brook draining east.  Hampstead Heath is capped by Bagshot Sands and water dissolves iron to produce Chalybeate Wells.  Springs occur at the junction with the Claygate Beds and drain into Hampstead and Highgate Ponds.  The latter was built as part of the late medieval water supply of the City of London.  The official source is the Vale of Health, one of the few places in London where bubonic plague did not occur but now a damp frost hollow.  The other arm of the Fleet arises near Kenwood House and the two arms join just north of Camden Town Station.

In 1800 it flowed down to St Pancras Station and there are paintings of bathers in the Fleet in 1815.  It passed by Smithfield Market, where the traders were allowed to draw off water to wash their meat but not to discharge into it (though they often did).  It became hemmed in by houses and rapidly became an open sewer.  It flowed past the Fleet Prison, Fleet Bridge and Bridewell in 1670 and there was a major attempt to revitalise the river (by Sir Christopher Wren) after the Great Fire of London.  The aim was to have the lower part of the Fleet as a Venetian style canal.  The area north of Fleet Bridge was covered over and became a market and there are remnants in street names such as Turnagain Street, Newcastle Street (the coal trade) and Stone Cuttes’ Street (the Portland Stone trade).  The Romans also used the Fleet for unloading stone  and Kentish Rag has been found in a ship at the mouth of the Fleet (one of 1500 loads recorded as being used for building the Roman wall of Londinium.

The river Fleet does not enter the Thames any longer.  In the mid-19^th century, Bazalgette designed a series of interceptor sewers with a 10 feet per mile gradient (self-flushing).  The Northern low-level sewer goes to a pumping station in Stratford where it is pumped to the Northern hihgh-level sewer, which has a natural fall to the Beckton treatment works.  The sewers take water from the Highgate arm and the middle and lower levels of the Fleet to assist flow.  However, the former outlet of the Fleet is still visible near Blackfriars Bridge.

River Tyburn

From the Belsize Park area, the River Tyburn crosses the Regent’s Canal in a culvert then into Mayfair where it was called the St Mary bourne or stream to avoid the unsavoury connotations of the name Tyburn, hence with several changes in spelling to Marylebone.

Water from the Tyburn has been taken from the 13^th century with conduits into the City of London via 3 miles of piping to Cheapside.  The Tyburn valley is distinct in Green Park but the river was probably dry or just a trickle by the 1500s.  It reached the Thames at Westminster with distributaries either side of Thorney Island.  South of Buckingham Palace the land was very flat and TAchbrook Street might be a 17^th century artificial cutting for floodwaters through Pimlico to Vauxhall Bridge.

Nick Bessant

This profusely illustrated talk covered the reptiles and amphibians of two areas in the southern United States of America, together with birds, mammals, invertebrates and flowers seen on springtime family holidays.

South Carolina

South Carolina is a warm weather area on the east coast of the USA.  It is largely flat and low-lying and very marshy with lots of rivers and lakes.  It has a mix of northern and southern species and a large number of different species.  It is relatively warm in spring and has holiday resorts on the coast for those in the family who are not dedicated to reptiles.

Compared to the UK’s 3 snakes, 3, lizards, 3 frogs, 2 toads and 3 newts, South Carolina has 39 snakes, 12 lizards, 16 tortoises and terrapins (+ 5 marine turtles), 1 alligator, 31 frogs and toads and 35 salamanders and newts.

The holiday was based at Hilton Head Island, a sand-spit island at the southern end of the South Carolina coast linked to the mainland by a causeway.  The island is very marshy with lots of lakes, including one just outside the time-share apartment.  The first alligator seen was on this lake, which also had abundant yellow-bellied sliders (terrapins).  A 10-12 feet long alligator was on the golf course nearby.  It is worth noting that it is an offence to feed or harass alligators.  Other species seen around here included fishing or raft spiders, dragonflies (Dolomedes sp.), great blue heron, snake-neck or anhinga, osprey, tri-coloured heron, black-crowned night heron, tufted titmouse and a flock of cormorants.  A green anole lizard was seen in the wall beneath the apartment.

A male southern toad was seen in the local shopping mall and a green anole displaying with its dewlap on the roof of a shop.  The local beach had sand dunes behind and a disorientated baby terrapin was seen making its way towards the sea.  On the golf course, they were shown an alligator den under the bank of the lake for winter hibernation.  Birds seen included brown pelicans, northern cardinal, eastern blue bird, little blue heron, pied billed grebe, red-bellied woodpecker, brown thrasher, northern mocking bird, great egret, white-throated sparrow, yellow-rumped warbler, brown-headed cowbirds, blue jay and grackle.  A south-eastern 5-lined skink was seen hiding in the leaf litter, presumably to escape cats, which predate them, though the cat almost comes off worst as they are toxic to them.  Spanish moss was abundant on trees.

On the way to the Tilman Sands Heritage Preserve, a black vulture was seen circling over Walmart and there was a boat-tailed grackle in the car park.  The reserve includes swamp cypress with its breathing roots.  A Carolina wren nest was found in an old tyre and there were zebra-tailed swallowtail butterflies and locusts. Dwarf salamanders, which have no lungs and just use the mouth and skin for respiration were found, as well as eastern fence lizard and ground skink.

The Gopher Tortoise Reserve is a dry area with very sandy soil.  The gopher tortoise digs long tunnels up to 40 feet down, which are used by many other animals as refuges.  In the harbour were laughing gulls, brown pelicans and a double-crested cormorant.  A dolphin-watching trip out to sea was successful.

At the Sea Pines Nature Reserve, a green tree frog and a southern leopard frog were seen as well as a ribbon snake eating a small frog.  Other species included red-bellied woodpecker, white ibis, grey catbird and grey squirrel (in its natural habitat).  The Sugar Cane Reserve had numerous mosquito fish, a common snapping turtle, a banded water snake, squirrel tree frog and a juvenile cottonmouth (water moccasin).  ~There were ant lion pits in the car park.

Northern Georgia

This holiday was at Big Canoe, Georgia, a gated community for residents and visitors on the edge of the Blue Ridge Mountains in hilly mountainous terrain, a very different habitat from that on Hilton Head Island.  As a result the species were different, with 12 frogs, 22 snakes, 8 lizards, 21 salamanders and 5 toads recorded on the species list.  

Birds seen included pileated woodpecker, red-headed woodpecker, Carolina wren (inside the apartment), chipping sparrow, tufted titmouse, American goldfinch, killdeer (a type of plover), eastern bluebird, vulture, wild turkey and Canada geese (in their natural environment).  Mammals included Virginia opossum, common raccoon and white-tailed deer and there were cockchafer beetles, a skipper butterfly, tent caterpillars and monarch butterfly as well as sapsucker damage to trees.  Fresh road-kill seen comprised a garter snake which had just regurgitated its lunch of red salamander.  A 5-lined skink or south-eastern 5-lined skink was seen as well as a 3-lined salamander and a black-bellied salamander.  In some of the lakes, trout have been introduced for anglers after killing off the native fish and this has tended to reduce the population of salamanders.

At the Amicolola Falls Park there was a reptile display in the information centre, which included eastern box turtle, copperhead (a pit viper), timber rattlesnake, eastern garter snake, corn snake and northern water snake.  In the park they saw tiger beetles, eastern tiger swallowtail and black swallowtail butterflies, eastern fence lizard, 5-lined skink, bullfrog and bullfrog tadpoles and a groundhog or woodchuck.  Birds included Blackburnian warbler, cedar waxwings, tree swallow, eastern bluebird, killdeer, broad-winged hawk and mourning dove.  Climbing up alongside the waterfall it was surprising to see a northern water snake on the rocks well away from the water, which turned out to be hunting Ocoee salamanders on the edge of the waterfall.  There was also a southern ring-necked snake.

The Dahlonega gold mine is now owned by the state as a tourist attraction and it was still early enough in the year for there to be bats hibernating inside.

At Toad’s Pond there was a stump which had been taken down by  beavers and green frog tadpoles, northern cricket frog, spring peeper (a tree frog) northern banded water snake and black racer snake.  Birds included northern flicker (a woodpecker), downy woodpecker, Carolina wood duck, greylag and Canada geese and turkey vultures.