One of these instances was in a lesson for Guitar World Online in about 2001 that included a transcription of the bassline live Zep recording seekers recognize from the intro of 1969 versions of Howlin' Wolf's "Killing Floor."
Guitar World also featured the bassline from "Black Dog" with accompanying text about how the one bassline inspired the other (and, subsequently, how "Black Dog" riff evolved in its development).
The original URL of that feature was here, although it's no longer online; however, one can retrieve the text of this feature via the Internet Archive Wayback Machine. I copied the relevant portions here though, and Jonesy's discussion begins as follows:
Let's begin this first lesson by talking about what I've often heard people refer to as the classic Led Zeppelin "stomp groove." A prime example of this can be found in the song "Black Dog," from our fourth album.
As you probably already know, Led Zeppelin was heavily influenced by blues music-Robert Johnson, Howlin' Wolf, Elmore James, Muddy Waters, B.B. King and many others.
At this point, the Guitar World Online page included the sheet music, seen here, and a WAVE audio file for the riff we recognize as the intro to Zep's live versions of "Killing Floor." For Mac users (like Jonesy himself), it also included an AIFF file. Alas, these files are no longer retrievable. Jonesy continued:
I was inspired to write the "Black Dog" riff after learning this old blues riff in E (see Figure 1) from the Muddy Waters album Electric Mud (Cadet, 1968). It's a swampy, circular, single-note riff and Jimmy Page and I used to love to play it forever! I wanted to write an original riff that had that same type of busy, yet plodding, feel.
His use of "single-note" means no more than one note is played at a time, rather than that the riff is composed entirely of a drone or repeated note of one pitch. At any rate, there you have it: the claim that it's from Electric Mud.
However, that's a whole album, not a song. So, it must be on one of the tracks, right? Well, if so, you should be able to go back to that album and listen for that precise riff. You can do that until the cows come home, and you'll never find it anywhere on that album.
It is, however, on the track "Smokestack Lightning" from the Howlin' Wolf LP in 1969, recorded with the same intentions as Electric Mud: to make a bluesman look silly doing some psychedelic music that, who knows, might actually earn some younger-generation fans who'd previously overlooked him.
So, what happened? It's my contention that -- gasp! -- Jonesy make a mistake. (Hell, he called me out on a mistake in my newsletter once, so I'm just repaying him the favor.) The two albums are similar in spirit, so he just got them confused.
But that's not the only instance of him citing Electric Mud as the source, is it? No, it's not. He certainly goofed up a number of times!
You know how you learn something wrong, and you can never get it right? Especially if you are never told that it is wrong?
Then we all started reciting it as fact. If Jonesy said it, it must be true. And if Jonesy said it five gazillion times, it must be really, really true! So, we learned it wrong, and he kept saying it wrong year after year, interview after interview. Until somebody stopped him. And that somebody was yours truly.
On Dec. 10, 2001, I interviewed John Paul Jones for four hours. At one point, he and I sang the riff together, and I asked him where it was from. He said Electric Mud. I told him I had that album on CD and I couldn't find the riff anywhere. He said he could be wrong but didn't suggest any alternative. And life moved on for both of us.
The following April was when I discovered where it was really from. I bought the Howlin' Wolf LP from 1969 on eBay and played it for the first time on April 26, 2002, on the 33rd anniversary of the third of four San Francisco shows that week at which Led Zeppelin played that very riff. In my April 27, 2002, edition of "On This Day In Led Zeppelin History," I wrote that the correct source of that bassline is Howlin' Wolf's LP. But he didn't necessarily read that newsletter, did he? Good thing my story doesn't end here!
Two years later, on Aug. 19, 2004, I greeted John Paul Jones on the closing night of his tour with Mutual Admiration Society. I held up the 1969 Howlin' Wolf LP cover to him, which reads, "This is Howlin' Wolf's new album. He doesn't like it. He didn't like his electric guitar at first either." Jonesy saw me and knew exactly what I wanted to talk to him about. While he was signing items for other fans, he talked to me, and I told him this album's third track was the source of that riff. Taking my word for it, he admitted that he'd been wrong all those times in the press when quoted on Electric Mud. I offered Jonesy to take the LP back home to England with him for old time's sake. Instead, he let me keep it -- but now with his autograph scrawled on the front.
If I wasn't entirely sold on the album by then, I like it just fine now.