Excerpt from Padre Island National Seashore Field Guide Pass Grasslands Nature Trail. The northwest trending grassed ridge is a stabilized longitudinal dune ridge left behind when the back-island active dune field passed over this area. The grassed flat is a deflation flat, formed by wind erosion of dune sand down to the level of damp sand. Pass another stabilized longitudinal dune ridge, shown in fig. 2. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.