This is a fine drawing in charcoal on sketch book paper (see the perforation holes at left), 8 3/4" by 11 3/4", signed at lower right by California and Massachusetts listed artist DAISY MARGUERITE HUGHES (1882-1968). Hughes was born and died in Los Angeles but in between she spent much time in the Provincetown art colony on Cape Cod. Considering the subject matter of this drawing, I would think it likely that this is a scene somewhere on the Cape, an image of one of the quiet estuaries, tidal marshes and small boat anchorages that dot that region. There's no date but the paper appears to my eye to be of post-World War II vintage (no watermark visible). Hughes exhibited widely (even at the Paris Salons) and was a member of many art associations. Her paintings of Provincetown houses and streets are quite popular at auction on the east coast, but she is also widely thought of as a Southern California artist. This drawing is in very good condition, and is presently just in an old mat, so, it needs to be properly framed. There are some very light handling creases at top right well out of the image area. There is a brown foxing spot just to the right of the signature and a tiny bit of smearing of the charcoal but it is really not noticeable. The "curve" of the paper apparent in the image is just the fact that there's no support behind it while the photo was taken. Paper is indeed flat and rectangular. See the net for more examples of Hughes' work.
DAISY MARGUERITE HUGHES (1882-1968) charcoal sketch of small boat anchorage probably Cape Cod Massachusetts