I am a bit slow on the uptake sometimes. It took me awhile to regularly use the Neogene and the Paleogene instead of the Tertiary period. I am dreading the day when the Quaternary will no longer exist. But last month while in the Canyonlands I noticed that one of my favorite formations apparently does not exist. No its not some revisionist erosion but a change in naming.
Elephant Canyon is a really fun little canyon deep in the Needles. The canyon bottom has miles of a classic grey/ greenish grey limestone that is full of obvious Permian fossils. It was always a joy to walk the length of the canyon right on the bedding plane between the limestone below and the Cedar Mesa sandstone above. The problem was that the mappable unit called Elephant Canyon Limestone is just not that easy to determine, so for years maps have shown that the Elephant Canyon was inter-fingered with the Halgaito Formation. But now, I see that the Halgaito formation is inter-fingered with the Lower Cutler.
To make the area a little more complicated, just a little bit to the west, the whole sequence of rock units is lumped into the Culter-undivided. Who thought up this system?
Not only does this give me a great excuse to do more research in my favorite place in the world, but I have to learn a new naming system. As any teacher will tell you, I have only so much room for names and that was filled way back in the mid-90's, so wish me luck.
The old stratigraphic column. Taken from the NPS web site. Notice down in the Permian that the Elephant Canyon is listed with the Halgaito Fm. You may have to click to expand.
The new stratigraphic column in miniature font. Please click it to read! Again, down in the Permian the Halgaito shale is now interfingered with the Lower Cutler.