What soil classification corresponds to having 60% or more rock fragments by volume?

The classification of soil as "Extremely Gravelly" is appropriate when it consists of 60% or more rock fragments by volume. This classification is based on the composition and particle size within the soil. Soil types are categorized by the predominant materials present, and when the rock fragment content is high, it significantly influences the soil's physical properties, including drainage capacity, stability, and vegetation support.

The classification system helps in understanding different soil types for purposes such as construction, agriculture, and environmental management. In the case of "Extremely Gravelly," the high ratio of rock fragments indicates an abundance of larger particles, which affects how water moves through the soil and how easily plants can take root.

In contrast, soil classified as "Very Gravelly" or "Gravelly" would have lower percentages of rock fragments, specifically under 60%. Sandy soils, on the other hand, primarily consist of smaller particles and do not contain significant amounts of rock fragments. Therefore, the term "Extremely Gravelly" is specifically used to denote soils with a very high volume of coarse materials, making it the correct classification for the given question.