Occasionally lightning strikes the sand, fusing it into a little tube or ball of glass. These fulgurites have been found here but are very rare and a real “discovery.” _Glacial Till_ The original soil deposited by the glacier may be seen by digging into the sand at the drumlin. Such rocky soil is quite surprising to people who think the beach is nothing but a big “sand pile.” _Garnets_ Examine a handful of sand. You will find that it consists of light-colored particles (mostly Quartz) and of black particles. Under a microscope many of these dark particles look like little gems. They are actually a deep red and are true Garnets. Large Garnets are used as gem stones, small ones for sandpaper—further proof of the abrasive ability of windblown sand. _History in the Sand_ In your handful of sand you may find particles that are neither Quartz nor Garnet. Minerals such as Feldspar, Biotite, Mica, Magnetite, Hornblende, and others can be identified by the geologist and are a clue to the original type of rock over which the glacier moved. _Beach Porcupines_ These are hard-packed balls of twigs and grasses. Loose vegetable matter is very light and may be blown along by the wind for many miles. As it goes it adds other vegetation to itself, until packed into a very tight, hard ball. It may also get its start in the water by being whirled into a tiny ball; and later it is thrown onto the beach, to begin rolling along. A most curious souvenir! MORE ABOUT THE DUNES The face of the land is a storybook waiting to be read. The following books will help you piece together some of the story: Henry Curtis Ahl, _Dunes and Beaches of Essex County_. Boston: Massachusetts Audubon Society, 1949. $.25 N. E. Chute and R. L. Nichols, _Geology of the Coast of Northeastern Massachusetts_. Massachusetts Department of Public Works and U. S. Geological Survey Cooperative Geologic Project, Bulletin #7. Boston, 1941. Out of print. Available in Museum of Science Library. John Henry Sears, _The Physical Geography, Geology, Mineralogy and Paleontology of Essex County, Massachusetts_. Salem, Mass.: Essex Institute, 1905. $6.00 Charles Wendell Townsend, _Sand Dunes and Salt Marshes_. Boston: L. C. Page, 1913. Out of print. Available in Museum of Science Library. ——, _Beach Grass_. Boston: Marshall Jones, 1923. $3.50 Chapter 2 AN INTRODUCTION TO DUNE ECOLOGY