Mohave or Mojave Pitcher with Frog Effigy

"Yuma" is written in  between the vessel's handle and the frog's chin.

Orange coloration could be poster paint.

"Unknown artist" is appropriate when a work of art is unsigned and a supported opinion about who made it is not available (on Savvy Collector).. "Attributed to" precedes the name of an artist when information suggests that it likely was made by that artist (on Savvy Collector).