Thomas Burch and family are listed in: Albemarle County in Virginia: giving some account of what it was by nature, of what it was made by man, and of some of the men who made it by Edgar Woods. The full text of this book is available on Google Books.
Also, a list of Thomas's children can be found in Mary Johnson's will. The will was probated in Philadelphia, PA on 15 May 1761. An abstract of the will is in: Philadelphia County Wills, 1682-1819. Historical Society of Pennsylvania, 1900, available on Ancestry.com