Thurlo is an old Newbury name, and in my search for paintings in the public domain of Newburyport I came across this painting.
The Painting is by Frank Thurlo who lived from 1828-1913. It is a watercolor on paper, of Plum Island River and Marshes, 4 1/8″ x 12 1/8″. And it is signed lower right. You can click the image to enlarge.