Charles Darwin in the Cordillera Mountains, in 1835

'The rivers which flow in these valleys ought rather to be called mountain-torrents. Their inclination is very great, and their waters the colour of mud. The roar that the Maypu made, as it rushed over the great rounded fragments, was like that of the sea. Amidst the din of rushing waters, the noise from the stones as they rolled one over the other, was most distinctly audible, even from a distance. This rattling noise, tight and day, may be heard along the whole course of the torrent. The sound spoke eloquently to the geologist; the thousands and thousands of stones, which, striking against each other, made the one dull uniform sound, were all hurrying in one direction. It was like thinking in time, where the minute that now glides past is irrecoverable.'

'The Voyage of the Beagle', March 7th, 1835.

 

Michel de Montaigne on River Erosion

Montaigne, the great inventor of the essay, wrote and speculated about everything, including the geology of his beloved river.

‑‑‑'When I consider how my local river the Dordogne has, during my own lifetime, been encroaching on the right‑hand bank going downstream and has taken over so much land that it has robbed many buildings of their foundation, I realise that it has been suffering from some unusual upset, for if it had always gone on like this or were to do so in the future, the whole face of the world would be distorted. But their moods change: sometimes they incline one way, then another: and sometimes they restrain themselves. l am not discussing those sudden floodings whose causes we know. By the coast‑line of Médoc, my brother, the Sieur d'Arsac can see lands of his lying buried under sand spewed up  by the sea: the tops of some of the buildings are still visible: his rents and arable fields have been turned into very poor grazing. The locals say that the sea has been thrusting so hard against them for some time now that they have lost four leagues of land. These sands are the sea's pioneer‑corps: and we can see those huge shifting sand‑dunes marching a half‑league ahead in the vanguard, capturing territory.'­

From Michel do Montaingne, 'On the Cannibals', page 5,
Translated by M. A, Screech, Penguin 60s.

Reading this recently on the bus I must have dozed off, for I remember that it continued as follows:-

‑‑‑ ‘Thinking again about my own river, the water is still encroaching on the right bank, but the river takes and the river gives back. You see the sand bank on the left: it grows higher each year. Already coarse grass is growing. Perhaps my grandson, or great‑grandson will farm that land. –­‘

When I came to type this passage I could not find it. Montaigne continues about the inhabitants of South America, the subject of his essay. There is no mention of the left hand river bank, so clearly I had invented this passage in a half doze, translating what I knew of rivers perpetually changing the surface geology of the Earth, laying down gravel beds and moving away, as some ancient river must have done in Maida Vale, North London.

Many houses there have basements dug out of a gravel soil. The proof that the soil was gravel is the presence of the basements, for no builder would have dug cellars to be lived in, in a clay soil. The clay would have held the water and people would have drowned. The gravel below Maida Vale did not arrive from nowhere. It was laid down by a huge river system many, many years ago.

The school in Oakington Road, Maida Vale was built on the basement sites of houses bombed in the Second World War and these basements were in gravel, so a river must once have flowed through the whole area. To add complications ‑ between the school playground and Shirland Road is a cutting, with the River Westbourne deep below, confined out of sight in a culvert. The river is on its way to the Serpentine, Chelsea and the River Thames. For centuries the Westbourne has been cutting through and below the gravel beds of a much older river.

In fact the River was the Thames in one of its earlier beds. At this time the River flowed across a huge sandy delta which skirted Primrose Hill. It flowed through the Finchley Gap to enter the sea in the Essex coast.  Later this course was blocked by ice millions of years later and the River cut the third bed which it uses today.  The gravel and yellow sand can still be found today whenever workmen dig near Warren Street Station. When the Orange building was under construction in Paddington Basin The builders found a deep bed of brilliant yellow sand which would make any beach famous. It had been left by the Thames millions of years before. The builders scooped it into lorries and sold it immediately to a concrete making firm. Having laid in peace for millions of years, it became ready-mix concrete inside days.


Picture of the Orange Building site on Paddington Basin in 1901

The picture shows the corner of Paddington Basin where the Canal turns into the Basin, The Basin is seen on the left, while the Canal, lined with small buildings, is hidden behind the end of the site. On the left the canal reflects some of these white-faced buildings in a slightly puzzlingway..

The site was so large that no normal camera could cover it in one shot. It had to be photographed in pieces and the n pasted together in the best way possible. The different perspectives clash somewhat but the final resuly is better than nothing.

The problem was to dig down safely and to keep the ground dry on a site with water on two sides.  The structural engineers bored a line of deep holes, just touching each other, around the site. They filled them with poured concrete   to make a continuous line of concrete below ground. At this stage they had merely bored holes and filled them with concrete. They had not started digging away any soil, so there was nothing to show for their work. It was all below ground.

Then they dug away the soil in the centre to make a funnel shape and built a small concrete foundation in the centre as a site for the tower crane. When the crane was first built into position, the ground sloped from the bottom of the crane to the top inside edges of the surrounding ring of concrete pillars. By this time they had excavated down to the brilliant yellow beach sand left by the River Thames delta millions of years earlier. Remember that this was not the bed of the present Thames, but a much earlier one which laid down the yellow sand under Warren Street Station and Euston Road. The sold the sand and it became ready-mix concrete.

Lastly, they removed the remaining soil in sections right up to the concrete pillars, poured more concrete to unite  the round pillars into a smooth, strong wall and cast the heavy capping ring on top to hold them all together. Today all this work is hidden but at the time it was a considerable feat of engineering, carefully planned and executed.
 

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