[16]Convolute beds show their layers thrown into a series of folds (some quite irregular) which result from the pressing weight of overlying sediments on highly plastic layers beneath. Some feel that these folds were the result of actual flowage of the layers in the direction of their tilt, and others credit the distorted bedding to the pressing weight of large boulders. These dragged across the layers while still frozen to overriding glacial ice. [17]The author noted both _Macoma groenlandica_ and _Saxicava rugosa_ (see Fig. 10 and Plate 1, Sketches 3 and 4). [18]Fossils are the preserved evidence of past life (animal or plant) as found in rocks or sediments, for example, the clams found in the clays. They may be direct evidence, such as the actual shells or mineralogically replaced shells of long-dead animals; or indirect evidence, such as the tracks or trails of animals now preserved in rocks. [19]Geologic time is divided into four Eras which are designated from oldest to youngest: Precambrian, Paleozoic, Mesozoic, and Cenozoic. Each of these Eras is divided into geologic Periods of time. The Ordovician Period is next to the oldest Period of the Paleozoic Era. This Period began some 420 million years ago, and ended approximately 360 million years ago. [20]Present Arthropods include the insects, spiders and crabs. Arthropods, which are invertebrate animals (without backbones), are characterized by jointed legs, chitinous outer covering and segmented body parts. Trilobites were very numerous in the early Paleozoic seas, but became extinct before the end of that Era. [21]The folding and the faulting of the Ordovician rocks took place sometime between the closing phases of the Ordovician Period and the beginning of late Silurian time (between 360 and 330 million years ago). Usually these earth movements are ascribed to the Taconic Disturbance which took place at the end of the Ordovician Period. [22]A walk along the beach in the direction of Button Island or “sickle point” (west and then south from the northern boundary of the Park) traverses the following geologic formations: the Glens Falls limestone which can be seen on Ship Point (actually an island off the northern end of the Park); the Orwell limestone, seen on Button Island; the Valcour formation which makes up “sickle point”; and the Crown Point limestone which is found on the Basin Harbor-side of “sickle point.” These rock units belong to the Chazyan Stage (Crown Point limestone and Valcour formation) and the next younger Mohawkian Stage (Orwell and Glens Falls limestones) of the Middle Ordovician Champlainian Series. Transcriber’s Notes —Silently corrected a few typos. —Retained publication information from the printed edition: this eBook is public-domain in the country of publication.