Describes the origin of limestone caverns, using Mammoth Cave as an example, with particular reference to the importance of groundwater information of caverns, the present condition of groundwater, and how caverns develop within fluctuating groundwater zones. (BR)

Describes activities that can be done before and during the Solar Eclipse that is to occur on Saturday, March 7, 1970. Examples are: making a sun clock, charting the path of the sun, tracking the moon, predicting the eclipse, measuring the size of sun and moon, and observing the eclipse. (BR)

Instructions for observing the Solar Eclipse on Saturday, March 7, 1970, which will be total along a strip about 85 miles wide along the Atlantic Seaboard. Safety precautions and how to construct a pinhole camera to observe eclipse. (BR)

Discusses characteristics of sand, its derivation, various colors, shape, grain size, how it is transported, how sand dunes are formed, and economic uses. (BR)

Discusses U.S. National Parks as natural laboratories for the study of ecology, geology, earth science, and botany. Suggests activities which will enable children to more fully appreciate the great age of the earth, its history, the complexity of its structure and composition, and the myriad plants and animals which inhabit it. (BR)