Day: July 26, 2018

Deep in a cleft in the steep, rocky hillside topped by the Eglise Saint-Pierre lies the Fosse Dione, a large karst spring.  “Karst Spring” is a term for a spring that represents the end of a large underground river system, typically with a very large discharge.  In the case of the Fosse Dione, this spring has an immense capacity, and is deep enough at its mouth (initially 32 meters) that cave divers have dived the cave.

Ironically, much of the local information focuses on the wash house (or laverie) built around it in 1758.  Little is made of the spring itself, which is believed to be the reason that this area has been occupied as far back as it has.  The presence of this abundant source of pure flowing water certainly explains the choice of the area as an administrative center, the Oppidum of Tomodurum, by the Romans, and explains signs of occupationwell back into the Bronze Age.

The water flows up out of the spring, over a lip in the surrounding wall, and down through a narrow, steep natural course between houses and out to the Armencon.  Houses cling to the hillside above it, and a narrow street enters on one side of the cleft, loops over the spring, and back out the other side.

The flow from the spring varies, and was quite low when I visited, reflecting the drought at the time.  Still, as you view the pictures, try to imagine the situation one spring in January 1910, when the water flow was so great that the water level in the cleft was two feet above the level of the spring retaining wall!!

In addition to being a natural and historical marvel, it also reflects some of the historical understatement I found from time to time after this, and which I encountered again when I reached Montbard.

July 22nd started for me with a loud BANG, as the boat shuddered and shifted.  I’d slept in a bit and was startled awake, my first thought being “The boat has been HIT!”.  Charging out of bed and into the wheelhouse, I immediately noted there was nothing near me.  The port was calm, and I was both confused and puzzled.

Getting dressed, I went out to check the boat.  It took a few moments, but I finally determined the issue.  The DBA guide had warned the downstream end of the quay could be shallow at times.  I had been fine the night before, but morning had come, the canal opened at 9 AM, and two sets of boats immediately locked downstream out of the port, obviously cycling the downstream lock twice.  That served to let enough water out of the pound between the two locks (that served as the port) to dropthe water level.  The bang and shudder was Desormais’ stern end settling and then shifting on the bottom.  I was stuck!

I finally got some relief late morning as the upstream lock cycled several times.  I had moored where I did as I was late into the port the day before.  With boats now moving and the stern raised a bit, I was able to move the boat up the quay to a deeper spot, resolved to avoid bottoming

Tonnerre is large community that climbs up a steep hillside.  At the top of the hill is the Eglise Saint-Pierre (Church of St. Peter) constructed in the 9th century and extensively rebuilt following a fire in 1556.  There is historical evidence the area was already settled in the late Bronze Age, and was also the location of a Roman administrative center in the Roman Gaul period.  Much of the reason for settlement in this location is the Fosse Dionne, a large karst spring that will be covered separately.

The view from the church:  6A346059-FCD0-42E7-B729-51111C84226C

The Armencon flows through the lower portion of the town, and bridges over it connect the heart of Tonnerre with the port area on the canal.

In addition to the Eglise Saint-Pierre, on the way up the hill there is the Eglise Notre-Dame de Tonnerre.  Built in the 12thCentury, this church was heavily damaged in WW II but is still used for services.

One other building of historical note is a massive structure, the Hotel-Dieu Notre-Dame des Fontenilles, or the Old Hospital.  Founded in 1293, it was the first and largest hospital in Medieval France.  It could treat up to 40 patients at a time.  (Note:  Hotel-Dieu is the term given to any Medieval hospital, of which there are a number of note in France, including the hospital in Beaune, which Suzanne and I visited in September, 2016)