T h e upper erosion surfaces of Norrh-east Wales are plotted and the evolution of the drainage system is traced. A warped and wasted envelope surface of Eocene age is recognized. There is evidence of a late h4iocenc peneplain at an elevation ranging from 2,200 to 1,800 feet. Into this have been cut numerous valley levels of Pliocene age from which the initial drainage of the Proto-Dec can be rrconsvuctcd and its subsequent break-up u a c e d * 1 0
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.