Order:

Testudines

Turtles and Tortoises

Families I've seen:

Chelidae Side-necked Freshwater Turtles	Cheloniidae Sea Turtles	Chelydridae Snapping Turtles
Emydidae Box and Pond Turtles	Kinosternidae American Mud and Musk Turtles	Pelomedusidae Afro-American Sideneck Turtles
Testudinidae Tortoises	Trionychidae Softshells