All downhill from now on?

Here is a puzzle to start today's posting.....Mark camped last night very close to that spot. In terms of the physical geography of North America it is very significant. I also think that psychologically it could be significant for Mark. So I will leave you to ponder it while we have a look at the route that took him there yesterday......
it was a day where he joined the Interstate 10 and travelled east across the Arizona/New Mexico border to his 'significant' overnight stop between Lordsburg and Deming.

Approaching the New Mexico border along the Interstate 10, the importance of desert rivers for irrigation and farming is again clearly visible. The river here is a small tributary of the Gila River (described in yesterday's posting) and it eventually joins the Gila downriver of the Coolidge dam (again referred to in yesterday's posting). San Simon is the last settlement in Arizona on the Interstate 10 before the border with New Mexico and is located in this valley. Some photographs and a little of its history can be seen here . This source includes reference to the fact that cotton used to be grown on quite a large scale around San Simon supplying a local cotton mill and providing local employment. Low cotton prices in the late 1990s forced a reduction in cotton acreage and as a result, the cotton gin closed.
Beyond San Simon the Interstate 10 rises to a plateau andthe New Mexico border . Approaching the border Mark would have seen the sign of welcome below ('borrowed' from the Panoramio layer in Google Earth)

....and just beyond the border there is a real ghost town called Stein's pass ! The story of this railroad town is linked to the history of the railroad and, in particular, to the change of power from steam to diesel. It is an interesting story which you can read by following the link above and also this one which offers the following..... Steins Pass today has a population of two. At its high point in 1919, the surrounding area supported more than 1,000 residents. By then , the town had a boarding house, two bordellos, a dance hall, several stores, saloons, and a hotel. But, for those early pioneers, life was tough in the desert region, as there was no source of water and it had to be brought into the area on the train, selling as high as $1.00 per barrel.

A very short distance east of Steins Pass is a small area of desert salt flats - a feature which we have become quite familiar with at places along Mark's route particularly in Iran and Australia.

Which brings us to the subject of the puzzle which I posed at the beginning of this posting? Last night Mark camped close to this location....

It was dark when he got there and he may well have missed the sign! It reads 'Continental Divide, Elevation 4585ft'. The Continental Divide is a line drawn down the Rockies marking the highest point between the rivers flowing west and the rivers flowing east and south . The technical name for this is a watershed. The line of the Continental Divide through the USA is shown on this map. There is plenty to read about it here but for Mark its significance is that from here its all downhill to the Mississippi!