Final answer:
The angular blocks of rock found at the base of slopes or mountains are known as talus or scree, formed from the accumulation of rock material due to weathering and erosion.
Step-by-step explanation:
The angular blocks of rock near the bottom of a hill or mountain are typically called talus or scree. These are accumulations of rock debris at the base of cliffs, steep slopes, or valley shoulders that have fallen from the adjacent rock faces. They are formed through processes of weathering and erosion, and their presence indicates historical rockfall events.
An angular unconformity is an example of such a process, where tilted layers of sedimentary rock have been eroded and new, horizontal layers have been deposited on top. Additionally, geological structures like faults can cause rock blocks to shift and accumulate at the base of structures. Whether termed as talus or scree, the composition and shape of these angular rocks are influenced by the geological history of the region and the type of rocks involved.