Carter's Grove (1751) in James City County is another Georgian type house, planned and partially constructed by Carter Burwell in 1751. The main unit of the mansion was constructed by the English builder, Richard Bayliss, and another Britisher, David Minitree. The mansion consists of two-and-a-half stories with wings on each side of one story. It is particularly noteworthy for its almost perfect symmetry. The main unit has a very high roof with a pair of large square chimneys. There are several dormer windows and the entire structure is 200 feet long. The interior as well as the exterior is beautiful with extensive pine paneling, a graceful arch across the middle of the main hall and exquisitely carved walnut railings along the stairway. Some officers of Lt. Col. Banaster Tarleton's troops used this place as headquarters in 1781. When Tarleton suddenly needed his troops, he rode horseback up the beautiful carved stairway. The horse's hoofprints are still observable on the stairway steps. Mount Airy in Richmond County was constructed by Colonel John Tayloe in 1758. This house is unusual because it was built entirely of stone, a rarity because the Tidewater area did not have an extensive amount of stone. Mount Airy is built of brown stone and trimmed with light stone furnishing a colorful contrast. The architecture of churches in Virginia is likewise varied. St. Luke's Church, originally known as the Brick Church in Isle of Wight County, is believed to be the oldest church still in existence in the original thirteen colonies. It is easily recognizable from its square tower and gabled nave. The brick Jamestown Church Tower (1639) is a Gothic structure also. The famous Bruton Parish Church in Williamsburg (1715) is an example of the change in architecture due to Governor Spottswood's planned improvement program for Williamsburg. This is the oldest Episcopal Church continuously in use in Virginia. Its cruciform construction of red brick is unusual with its numerous high, white shuttered windows. The square tower was built at a later date and seems to add dignity to the structure. Christ Church in Alexandria, constructed in 1767-1772, has characteristics of the late Georgian Colonial Period: red brick, a square tower with an octagonal-shaped belfry having a dome cupola, a trimming of white stone and a crown of Wrennish pepperpots.