Glacial potholes. The 'potholes' found in the chasm are products of a process called "rock drilling". Stones, or cobbles, are caught in the current and are bounced by the rushing water. The cobbles nick away at the bedrock creating deep circular holes.
"Sorry, but being a mother is not the most important job in the world. It's time to drop the slogan. It encourages mothers to stay socially and financially hobbled, it alienates fathers and downplays the importance of other significant relationships between children and adults."