I was surprised to read (Eos, 62(32), 618, 1981) that a Caltech-Gulf Research and Development Company gas emission monitoring study along the San Andreas rift zone has so far recorded no methane. The same story credits me with finding methane along the East Pacific Rise, in Tibet, and in other exotic locations. However, right here in our own backyard my laboratory has been monitoring methane emissions at more than a dozen sites for more than 5 years, on the San Andreas, San Jacinto, and Elsinore faults [Craig et al., 1980a]. These data have been reported to USGS at 6-month intervals, to Cal Tech on a number of occasions, and presented at AGU meetings [Craig et al., 1980a]. Your story clearly does not inspire great confidence in industry's exploration for new natural gas deposits.