Our mission last Sunday was nothing less than to locate and measure the biggest natural fossil fumarole pipe in the Primavera Forest – and (for all I know) in the entire world. Mr. Guinness, be advised: we found it!
So what’s this pipe? It’s a long round column of rhyolite rock formed long ago by a stream of water vapor bubbles rising through a pyroclastic flow, cooling the hot tephra and causing it to crystalize. Thousands of these natural cylinders – also known as fairy footstools – abound in the Primavera Forest, but most are less than half a meter in diameter.
Years ago I had spotted what looked like a big fossil fumarole above the River of Ghosts (Rio de las Animas) near the town of Tala, which lies about 30 kilometers due west of Guadalajara. Now, with the help of rugged outdoor enthusiasts Mario Guerrero and Maruca Gonzalez, I hoped to relocate and measure that fat formation.
We drove through Tala and into Villa Felicidad, famous for its wild and crazy Toba Tala rocks. Halfway through Villa Felicidad, we came to a spot where it looked like a tornado had cut across the dirt road. Our eyes popped and our jaws dropped. We jumped out of the truck. As far as the eye could see to the left and to the right, a long strip of the natural landscape had been ripped up, destroyed by countless bulldozers. The Macrolibramiento (outer Guadalajara ring road) has arrived!
Sad to say, it’s now only a matter of time before the chirping of birds in Villa Felicidad will be replaced by the roar of heavy traffic on its way to and from Mexico City and all points east and west. Goodbye felicidad!
We continued on to a parking spot above the River of Ghosts, walked down the trail to La Lobera Spring, a magical spot where cool, perfectly clean water gushes out of the ground and splashes into the river.
“This is a perfect place to camp,” said Mario, pointing to a flat area just above the river.
We proceeded upstream to a natural bathing pool, again right next to a flat area great for camping.
“Now, John, where is that giant fumarole you want us to measure?” my companions asked.
It took a while for us to spot the tips of two big cylinders halfway up the steep hillside on the other side of the river.
“The one on the right has got to be the fattest pipe I’ve ever seen,” I said. “All we have to do is get across the river.”
We soon found a narrow spot where we could jump across the stream and immediately we were climbing up a slippery, nearly vertical cliffside, Mario clearing the way with his machete.
On the way to the pipes, we found a shallow shelter cave with two man-made walls which did not look ancient at all. Who had chosen to take refuge in this remote, hard-to-reach cliffside? 
“No doubt it was some bandido who cherished the honor of camping next to the ‘Fat Fossil Fumarole,’” I said.
We quickly determined that this chubby cylinder measured 1.74 meters in diameter, by far the largest formation of this kind we’ve yet seen.
Celebrating our discovery, we returned to the waterfall for a picnic and a dip in the river.
This stretch of the Rio de las Animas is great for hiking, bathing and camping, but be prepared for jejenes. Yes, in the summer there are plenty of gnats and you need to lather on the repellent about every two hours. Also note that when the Macrolibramiento is finished, easy access to this fascinating area may also come to an end. Check it out before it’s gone!
How to get there
From Guadalajara take Avenida Vallarta and then Highway 15 (Nogales) west for 25 kilometers to Highway 70 which heads southwest towards Ameca. Go about 18 kilometers and you’ll come to an overpass and turnoff to Tala. Drive about 1.8 kilometers SE till you come to a Pemex gas station and a stoplight. Here (N20 39.150 W103 42.641) drive into Tala on Calle Morelos. Go east 1.6 kilometers and turn left (north). Drive 320 meters and you will hopefully be on Calle Luis Rojas. Now drive east, out of Tala and through Villa Felicidad for four kilometers to a fork in the road. 200 meters SE of this spot you can park (at N20 39.307 W103 39.426). Now walk 423 meters down a no-longer-drivable road and you will reach the Ghostly River. Cross the river at La Lobera Waterfall (N20 39.258 W103 39.171). Walk 275 meters upstream to the bathing pool and above it you’ll find the Fattest Fossil Fumarole at N20 39.329 W103 39.056. All these places are also easily reached from Lake Chapala via Cajititlán and Tlajomulco. Driving time to the River of Ghosts from either Guadalajara or the lake is about 75 minutes.