Into a Lava-Lined Underworld Near Albuquerque

The green plastic helmet I took off the rack looked a lot like a construction hard hat, except for the logo of a bat printed on the front.“Do I really need this?” I asked the park ranger behind the desk at the Northwest New Mexico Visitor Center, near the town of Grants. His name tag said “Anthony Sandoval,” and based on his tattoos — one of an antler, the other of a deer’s head inside an outline of the Land of Enchantment — I assumed he liked ven…