So in the later 1920s Cornwell spent time studying mural painting under Frank Brangwyn. Some of this style rubbed off on his illustration work, as I pointed out here.
When the city of Los Angeles had a new Public Library built, part of the concept was to include a good deal of interior art, as mentioned here. Included was a set of murals by Cornwell. The library's web site has a page dealing with him and his murals, including mention of critical appraisals.
Not long ago I came across some photos I took of the murals back in 2010. I used some tools on my iMac to enhance what were images of dubious quality. The better results are presented below. Because I fiddled with brightness, contrast, sharpness and the colors themselves, I suggest you pay more attention to Cornwell's compositions and drawing than to colors.