To my eye this drawing is just about a perfect thing, and feels like a happy surprise every time I look at it. I have found mention of a few different W.H. Voorhees', most notably a Mrs. W.H. Voorhees of San Francisco who was active in the temperance movement (mentioned in the local paper on a visit to see her sister in Ohio in 1886), and who donated a campaign ribbon for the first Republican Party presidential campaign (1856) to the San Francisco Museum of Art in 1896. I can't say for sure she made this, but it seems quite possible, and 2nd half 19th c seems right. It seems possible it was a school exercise, perhaps in making use of a compass among other things!
Ink over pencil, with hatching in blue and black/gray ink and what appears to be crayon for the other colors, except what looks like watercolor for the yellow, then multiple pencil drawn frames around the whole thing. And then at the bottom, what looks to be a little upside-down heart in pencil, with signature to the right.
Drawing measures 7 3/8" x 5 5/8". Framed, as found, in an old gold-painted wood frame that I think suits it perfectly: 8 5/8" x 7 1/4". Very good condition, and just a gem of a thing I think. Wired on the back for hanging.