GEOLOGICAL DISCOVERIES YOU CAN MAKE
Ventifacts
These small, faceted pebbles found in the dunes have been blasted by the windblown sand. They show the powerful abrasive action of the wind. Most of those you will find here were faceted just after they had been deposited by retreating glacial ice. A migrating dune or a blowout in the sand has left them uncovered.
Erratics
Large rocks occasionally found in the dunes are called “erratics.” In this world of tiny particles they appear very much out of place, but they were carried here by the glacier a million years ago. They have been uncovered by the migration of some dune.
Fulgurites
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!