You need to add disc marker GTO237 to your discussion. Its data sheet reads, 14,502.7 ft. (14496.5 + 6.1). This elevation should mean something being an order 3 vertical control marker. I have gotten different stories regarding the 14494 ft elevation. One story, as referred to above, is that 14494 is the average elevation between markers (why would an average be taken?). Confusing stuff. The other story I got from someone in the USGS is that the marker for the 14495 elevation was destroyed. Because of this, USGS had to use another marker one foot lower! The only way to resolve the growing confusion over the true elevation for Mt. Whitney is to place a GPS station on the truly highest point (on a rock not surveyor disc) on Whitney. This was never fully done, despite the article about the surveyor measuring the 4 highest summits in California by GPS. This is my last entry.