Houses usually of somewhat later date and notable for greater refinement of detail had gable-roof dormers with round-headed Palladian windows extending up into the pediment. As in the accompanying illustration showing a dormer on the house at Number 6105 Germantown Avenue, Germantown, the casings usually take the form of fluted pilasters, supporting the pediment with its nicely molded cornice, often, as in this instance, with a prominent denticulated molding. Narrower supplementary pilasters supported a molded and keyed arch, forming the frame within which the window is set. The lower sash is six-paned, while the upper one has six rectangular panes above which six ornamental shaped panes form a semicircle. Similar dormers, differing chiefly in ornamental detail, are features of Loudoun, Vernon, Upsala, Hope Lodge, Port Royal House, the Perot-Morris house, the Billmeyer house, the Wharton house, Number 336 Spruce Street; the Powel house, Number 244 South Third Street; and the Stocker house, Number 404 South Front Street. The dormers of Cliveden and Mount Pleasant are of this type but further elaborated by projecting ornamental scrolls at the sides. As the architecture of Philadelphia is almost exclusively in brick and stone, there were none of the architrave casings and ornamental heads consisting of a cornice above the architrave and often of a complete entablature which characterized much contemporary New England work in wood. Brick and stone construction require solid rather than cased wood frames let into the reveals of the brick wall and have no projections other than a molded sill, as on the Morris house, while a stone lintel or brick arch must replace the ornamental head, often such a pleasing feature of wood construction. The frames were of heavy construction held together at the corners by large dowel pins and were ornamented by suitable moldings broken around the reveals of the masonry and by molded sash guides in the frame. In the earlier brick houses the square-headed window openings had either gauged arches, as at Hope Lodge, or relieving arches of alternate headers and stretchers with a brick core, as at Stenton. Later, as in the case of hewn stonework, prominent stone lintels and window sills were adopted. Marble was much favored for this purpose because it harmonizes with the white-painted woodwork, brightens the facade and emphasizes the fenestration. Most of the lintels take the shape of a flat, gauged arch with flutings simulating mortar joints that radiate from an imaginary center below and mark off voussoirs and a keystone. Usually there is no surface ornamentation, the shape of the parts being depended upon to form a decorative pattern, the shallow vertical and horizontal scorings on the lintels of the Morris house being exceptional. These, the lintels of Cliveden and of the Free Quakers' Meeting House, exemplify the three most common types.