This was an oddball cartoon. The live action Lone Ranger TV series was still popular in reruns well into the 70s, and this cartoon started in 1966 and ran on CBS for three years, then was in syndication for a while after that. It pretty much disappeared for many years though. It wasn't until the late 90s that I got a VHS tape of two hours of the episodes that I saw it again. I did write about it in an old issue of Xenorama, but I barely knew anything about the cartoon then.
I only remember seeing bits and pieces of it as a very young child. I don't recall seeing it in the 70s, but I always knew it had existed, even after the Filmation version was done later on (I preferred this one at the time, though I enjoy the later one as well now, all things considered).
It's a pretty cool cartoon, very atmospheric, and Tonto got his own solo episode for all 26 half hours shows, pretty progressive for a show back then. He had an eagle pal named Taka that helped him out. The episodes are all in the 7 minute style, filled with The Wild Wild West style characters and situations. It's too bad the recent movie adaption tanked so bad (and looked even worse), we might have seen a release of this series to capitalize on the film.