The oldest part of Whitby Hall as it now stands was erected in 1754 by James Coultas, wealthy merchant, shipowner, soldier and enthusiastic promoter of many public and philanthropic enterprises. In 1741 he established himself in a house then existing on the plantation that corresponds to the present east wing, which was reconstructed with rare fidelity in 1842 to match the western wing erected by Colonel Coultas. The walls of the entire present house all around are of nicely squared and dressed native gray stone, and to afford extra protection against prevailing winds a penthouse with coved cornice runs along the northern and western ends at the second-floor level. The gables of the west wing face north and south with quaint oval windows to light the attic. A flag-paved piazza extends across the south front, forming part of the main entrance, while in a tower projection on the north front is located the staircase already described. Both the hall doorway and windows in this tower have brick trim, an unusual feature, while the bull's-eye light in the tower pediment, also set in brick trim, was a porthole glass from one of Colonel Coultas' ships.
As a merchant and in numerous other private enterprises, Colonel Coultas amassed a substantial fortune. From 1744 to 1755 he was the lessee of the[161] Middle Ferry, where Market Street bridge now stands, and it was chiefly due to his initiative that steps were first taken to make the Schuylkill River navigable. He was one of the commissioners who surveyed the stream and the first to demonstrate that large boats could be taken above the falls. In 1748 he was a captain of the Associates, a battery for the defense of Philadelphia against French insolence, and in 1756 during the Indian uprisings he became lieutenant-colonel of the county regiment. He was repeatedly justice of the peace, high sheriff of the county from 1755 to 1758, and in 1765 was appointed judge of the Orphans' Court, Quarter Sessions, and Common Pleas. He carried on a farm in Blockley, operated a sawmill on Cobb's Creek north of the Blue Bell Inn, was a devout vestryman and enthusiastic huntsman. He it was who laid the corner stone of the Church of St. James in 1762, and as a member of the Colony in Schuylkill and the Gloucester Fox Hunting Club he was also prominently identified with the more convivial activities of the community.
On Colonel Coultas' death in 1768, Whitby Hall was inherited by his niece, Martha Ibbetson Gray, and later passed by inheritance to her great-great-grandchildren in the Thomas family, in whose hands it still remains.
Eloquently typical of the broad hall running entirely through the house from front to back, with the[162] staircase located in a smaller side hall, is the arrangement at Mount Pleasant to which reference has already been made in a previous chapter. It is one which affords delightful vistas through the outside doorways at each end and an ample open space for dancing on occasion. Handsome doorways along the sides open into the principal rooms and are notable for their beautifully molded architrave casings and nicely worked pedimental doorheads. In fact, the woodwork here, as well as that throughout the house, is heavier and richer in elaboration of detail than usual in Georgian houses of the North, the classic details of the fluted pilasters and heavy, intricately carved complete entablature being pure mutulary Doric and more ornate than the Ionic detail of Whitby Hall. However, this was quite in keeping with the larger and more pretentious character of the former. The entablature is a positive triumph in cornice, frieze and architrave. The moldings are of good design and carefully worked; the guttæ of the mutules, the triglyphs with paneled metopes between, and the guttæ of the architrave all closely follow the classic order and exemplify the finest hand tooling of the period.
So similar as a whole yet so different in detail are the staircase hall of Mount Pleasant and the staircase end of the main hall at Whitby Hall that they invite comparison. In general arrangement they are much the same, except that the staircases are[163] reversed, left for right. As at Whitby Hall a flat arch frames the staircase vista, a great beam bearing the entablature surrounds the hall at the ceiling, spanning the entrance to the staircase hall and being supported by square, fluted columns. In this smaller hall a simple, though only a molded cornice in harmony with that of the main hall suffices. Unlike the plain dado of the main hall, however, elaborated only by a molded surbase and skirting, a handsome paneled wainscot runs around the staircase hall and up the stairs. The spacing and workmanship displayed in this heavily beveled and molded paneling could hardly be better. At the foot of the flight, on the landing and at the head of the stairs, the ramped surbase with its dark wood cap, corresponding to the handrail opposite, is supported by slender fluted pilasters which materially enrich the effect. The space under the lower run of the staircase is entirely paneled up with a small diagonal topped door opening into the little closet thus afforded. The scroll-pattern stair ends, balustrade and spiral newel treatment are much the same as at Whitby Hall. Although similar in pattern the balusters are more slender and placed three instead of two on each stair.
On the second floor, as below, the hall extends entirely through the house, and following a frequent custom of the time was finished in a different order of architecture, the pulvinated Ionic being[164] chosen, no doubt, for its lighter grace and greater propriety adjoining bedchambers. In furtherance of this thought, only the cornice with its jig-sawed modillions was employed at the ceiling and the flat dado was paneled off by the application of moldings to give it a lighter scale. The complete entablature was used only over the archway at the head of the stairs, where it was supported by square, fluted columns with beautifully carved capitals. Another mannerism of the time is the variation in the treatment of the doorways, the pedimental doorheads on one side being broken, whereas the others are not.