Westmoreland used several marks, but not, to the best of my recollection, an underlined W. (They had a W and G superimposed: W in a keystone and the word WESTMORELAND in a semicircle around III).
L G Wright used the W underlined within a circle - they also used what has come to be known as the (infamous....long story) "wonky N" which is a W with one side shorter than the others, to make it look like the Northwood N.
Other companies used an underlined W (Westinghouse and Wheaton, I think) but I feel pretty sure that we are looking at what Della said right at the beginning......L G Wright.
Glen