Terrace accretion is the process by which sediments are deposited on a slope in a series of terraces. This occurs when a stream or river erodes its bed and carries sediment downstream. As the stream or river flows over a slope, it deposits sediment in layers, creating terraces.

This process can occur in a variety of settings, including:

* Mountain valleys: Where glaciers carve out valleys and leave behind sediment that is deposited in terraces as the glaciers melt.

* River deltas: Where rivers flow into a larger body of water, depositing sediment and creating terraces.

* Coastal areas: Where waves erode the coastline and deposit sediment in terraces.

Therefore, you cannot say that terrace accretion happens on a specific mountain. It's a process that can happen on various slopes and landforms.