Carlos Alberto Santos, Mundo de Aventuras (first series) # 1128: "Drama em Orchre [sic] Flat," May 6, 1971 (the issue reprints "Marshall of Ochre Flat," [London] Evening News, December 19, 1968 - April 18, 1969).
Nikai Andrews asked me: "How did you come across Matt Marriott anyway?"
Here's my answer:
A lot of the Matt Marriott story arcs were
published in Portugal in a mag titled Mundo de Aventuras [a world of
adventures]. The production values were as poor as poor can get: with pulp
paper, layouts completely changed, drawings chopped up or expanded by some
hack, ugly mech types, balloons all over the art, etc... Since I think that the series improved
dramatically during the 1970s and production values in Mundo e Aventuras improved a lot, I was old
enough to be impressed by such 1970s tales as "Mary A Pregadora" ("Gospel Mary") or "Uma Nota de Dez Dólares" ("A Ten Dollar Bill").
As you can see below the production values of the ADCCC (All Devon Comics Collectors Club) aren't stellar exactly (I would say that they are uneven, being the example at hand one of the worst).
James Edgar (w), Tony Weare (a), Daily Strips # 144 published by the ADCCC (this issue reprints "Zincville Colorado," [London] Evening News, June 22, 1970 - October 10, 1970).
Even so, look at the strips above as a page in Mundo de Aventuras below. I don't even know where to start; I'll just say that the whole shebang is there and I don't need to repeat it.

James Edgar (w) [translator ?], Tony Weare (a) [with some hack], Mundo de Aventuras (first series) # 1201: "A História de Vinc Bill," [sic] September 28, 1972.
Those who read The Crib regularly know that I don't have a lot of respect for comics publishers and comics editors (small wonder, with examples like these), but it goes without saying that there are some exceptions like the great Héctor Germán Oesterheld (let's not forget that he was also a publisher; that's, of course, the only explanation to the question: how is it even possible that such stories were published back in the 1950s?). Chris Oliveros is another one, and let's not forget those guys at L'Association and Sins Entido and Frémok and Christian Humbert-Droz and Gary Groth and Kim Thompson (I miss you Kim!) and... and... I would not put those responsible for the second series of Mundo de Aventuras in the same league (far from it), but the fact is that they were responsible, during the 1970s, for three Matt Marriott comic books that respected the original material denying Mundo de Aventuras' terrible past (see below).

Tony Weare, Mundo de Aventuras (second series) # 23: "Uma Nota de Dez Dólares," March 7, 1974 (the issue reprints "A Ten Dollar Bill," [London] Evening News, May 9, 1972 - September 7, 1972). There's a Portuguese fanzine (or prozine) reprinting all the Matt Marriott strory arcs, but about that, the less said, the better.
When I was in my teens I loved Matt Marriott (strangely enough I loved Tony Weare's style - I also loved the work of Eric Parker, by the way), but I couldn't realize what to me today seems painfully obvious: as good as Eric Parker's drawings are Buck Jones isn't Matt Marriott. It's the difference between a childish, manichean, racist, comic book and an adult, complex comic strip. It's as simple as that.