Here is a list historic maps on the Internet that include Perkasie, Bridgetown, Benjamin and Rockhill Towhship.
Perkasie Sanborn Fire Insurance Maps
1912 Bucks County Road Map
The Fowler Map (1894)
The 1891 Noll Atlas (Paid Site – Free Map View)
The 1886 North Pennsylvania Railroad Atlas
(Paid Site – Free Map View)
The 1876 J.D. Scott Atlas (Paid Site)
The 1850 Bucks County Atlas
The 1831 Bucks County Atlas
1687 Map of Bucks County