A series of tape boxes belonging to engineer Ron Nevison will be going up for auction in March. As a tease, the auction house has uploaded a brief taste (embedded above) of rough mixes of two songs from Led Zeppelin's 'Physical Graffiti,' 'Kashmir' and 'Custard Pie.'

The clip of 'Kashmir,' which at the time was called 'Driving to Kashmir,' features the classic before the keyboards, orchestra and Robert Plant's vocals were overdubbed. 'Custard Pie' sounds mostly as it did on the record, but is missing John Paul Jones' Clavinet.

New Hampshire's RR Auctions will be selling off Nevison's collection -- 53 items in total -- as part of its Marvels of Modern Music auction, which will run from March 13-20. This includes rough mixes of songs by the Who, Eric Clapton and many others. You can read more about the collection on their website, and see the other items up for sale here.

Rolling Stone has a few more clips, including a mix of 'In the Light,' also from 'Physical Graffiti,' and Bad Company's 'Can't Get Enough.'