The "Hill" in New Mexico...

I have mentioned Local Legends in a couple posts but they just seem to keep on coming so today I hope to polish this road apple of wisdom a bit more.

D&RG 315 on "Hangman's Trestle" Colorado - D&RG Net

We were just started on a trip from Antonito to Chama when, in the open car, I asked, "What is a local legend?"  A passenger quickly responded, "Something local folks believe that is not true."  Pretty much correct but, sometimes there may be an element of truth underneath the legend.  The question is asked  as we are approach Fergueson's Trestle which is better known as "Hangman's Trestle" because it is a great example of a "Local Legend." In this case a miscreant named "Fergueson" was supposedly hauled out of town on a "borrowed" locomotive and thence hanged at the Trestle for doing some heinous deed, or deeds.  Fergueson may have existed and likely has a historic basis yet, no record of him has been found.  The "heinous deed or deeds" bids fair as the result of a fanciful story concocted over a cup of coffee on a cold winters night in some such place as the Big Horn Section House.  This story when enhanced by a true story worthy of the Marx Brothers namely, the destruction and rebuilding of the trestle as a result of an ill conceived movie stunt, hilarity always ensues at least for a brief moment.  When the gravity of this historical affront is fully taken in the smiles fade.  

The picture above is a light freight pulled by a beautiful locomotive the D&RG #315 but I would like you to look again taking a wider view of the landscape.  This isn't about Fergueson's Trestle it is about that oddly symmetrical hill just behind the train on Hangman's Trestle and another Local Legend.  This is today's story:

San Antonio Mountain at Lava Tank - Rio Arriba County, New Mexico

The "symmetrical hill" in the first picture is one of the most prominent landmarks on the Cumbres and Toltec.  From far out on the line, beyond Lava Tank and Big Horn Wye, you can see the Mountain either on the horizon or rising beyond a ridge above the Rio De Los Pinos.  It is so ubiquitous that you lose sight of it amidst the ongoing revelations on your journey.  At times it seems to loom over everything and at others it seems insignificant.  It all depends on atmospheric conditions and exactly where you are in the journey.  As you travel further away it can look huge and as you come closer it seems to shrink.  It's all in your mind's eye and the near perfect symmetry of the Mountain.   In the top picture the train is actually closer to the Mountain than the one below but it doesn't seem thay way.  Only one photograph, "The Vista Across the Rio Grande Rift Plateau", shows the totality of the Mountain.

San Antonio Mountain from the North on US 285 - Colorado

That "hill" is San Antonio Mountain, all 10,918' of it, is located in the far north end of the Taos Plateau Volcanic Field in New Mexico.  It rises as the highest point in the Volcanic field and is considered an excellent example of a "shield volcano."  The name is derived from an appearance similar to a soldiers shield lain flat on the ground in an upright position.  It supports the wintering of a herd of over 1,000 individual Elk.  It can also be observed from as far away as 60 miles on a clear day which is typical when on the floor of San Luis Valley to the north in Colorado and from above the Rio Grand Rift Plateau to the south in New Mexico.

"The Vista Across the Rio Grande Rift Plateau" - San Antonio Mountain and the Rio Grande Rift From the South
New Mexico

How San Antonio Mountain developed could involve a long diatribe about rocks and lava but not here.  This is about legends and such so I will just try to keep it brief.

San Antonio Mountain is the highest mountain in the Taos Volcanic Field in New Mexico through which the Rio Grande Rift has torn the surface asunder.  It was formed from flowing lava about one to four million years ago, which is after the last volcanic event in the San Juan Volcanic Field - the long and violent eruption of Los Mogotes Volcano - to the north and before the events in Yellowstone far to the north.  It is formed from flowing, or sheeting, lava  produced by the volcanic action which builds up in to a "shield" shape as progressive layers of flowing lava are laid down in sheets through ongoing eruptions.

Mount San Antonio is a dormant volcano of relatively recent geological activity within the past 1.5 million years.  The San Juan Volcanic Field is generally older than the Taos Plateau Volcanic Field and even younger fields with spectacular features are to the south and west around Los Alamos.

Moving on:

On one trip last year I heard a fellow of high repute state, "Locals say wisps of steam can be seen coming off San Antonio Mountain.  Perhaps we are in for some volcanic activity there."  Yet another long-time nabob of the rails took the time to loudly correct my comments saying, "There is a caldera at the top of San Antonio Mountain."  To both of which I unabashedly state, "Balderdash."

Time for a reality check:

The first of the comments regarding the issuance of steam from the mountain is pure wishful thinking which doesn't even rise to the level of Local Legend.  If there was any sort of activity such as steam venting every federal and state agency associated with planetary physics would be all over the thing - they aren't, and it would make international news - it hasn't.  So much for that topic.

The next assertion is the presence of a caldera.  I assumed this to mean an actual cavity such as that seen in the Valles Caldera of New Mexico, La Garita Caldera at Creede, Colorado or even Los Magotes Volcano/Caldera.  The answer to that assertion is presented in two Images.

The first is a topographical map from the USGS.  This map is the top of San Antonio Mountain.  At the top is a large relatively flat area - approximately a quarter mile across with a tiny bump at the southeast corner.  It is likely this may have been the location of an ancient caldera; it appears that is not now the case.

Topographical map of San Antonio Mountain - USGS

Then again, this is only a "map" and the actual surface may be quite different.  And, so it is.  High level images of the Mountain show large rectangular swaths of trees missing.  It is as if a giant razor has mown them down; the edge of one can be seen in the right hand side and top left of the picture below.  Such regular shapes are not found in nature and they indicate two things: the Mountain has been clear cut in numerous areas and, the Mountain is generally level enough for logging activities.

Further inspection of the picture notes a curious band circumventing the "Electronic Station" at the end of the National Forest Road.  This does not appear to be cleared and may be a rock outcropping upon which trees cannot readily grow.  If the latter is the case the curvature could be indicative of the remains of a large volcanic outcropping associated with a small caldera.  This would fit with the overall character the volcanic structure.

The final image is a broad overview of the topography associated with the Cumbers and Toltec Railroad.  The yellow line wandering through the image is Colorado/New Mexico Why 17.  The Railroad generally follows to the south of that highway.  Antonito, Osier and Cumbers, Colorado are noted as is Chama, NM.  The railroad crosses the State Line 11 times and the valley of the Rio De Los Pinos and Toltec Gorge are very clear - this is the route of the railroad.   To the south and east you will note a the telltale round shape of a volcano circled with a red line.  This is Mount San Antonio.

Aerial view of the crest of San Antonio Mountain - Google Image

Conejos & Archuletta Counties, Colorado & Rio Arriba County, New Mexico

We can revel in Local Legend and speculation but the story needs no aggrandizement;  when passed to others with honesty and candor its wonder and beauty will be revealed in the telling.

The story of the Denver and Rio Grande San Juan Extension National Historic Monument is told in three parts: the People and the Railroad but first of all, the Land.  To truly know the story you have to understand all the parts and that is the task, and happy duty, of a docent - as I understand it.

j