Pseudopodia Temporary protrusions of the protoplasm of a protozoan, which serve for locomotion or grasping. The second period of the Cenozoic era, spanning the time between 1.8 million years ago and the present. A microscope in which a finely focused beam of electrons is scanned across a specimen, and the electron intensity variations are used to construct an image of the specimen. This type of microscope is ideal for magnifications from 200 to 35,000. Sediment Solid unconsolidated rock and mineral fragments that come from the weathering of rocks and are transported by water, air, or ice and form layers on the Earth's surface.
Sediments can also result from chemical precipitation or secretion by organisms.
Sedimentary Rock A rock that is the result of consolidation of sediments. Silurian A period of the Paleozoic, spanning the time between 440 and 410 million years ago. It is named after a Celtic tribe called the Silures. The branch of geology concerned with the formation, composition, ordering in time, and arrangement in space of sedimentary rocks. Subtropical Bordering on the tropics or nearly tropical.