In daylight, if the stones were dry, a man with steady nerves could use the path, but when slab and scree were packed with snow nothing but a Herdwick could cross it safely.

The dogs knew this and were trying to hold the flock.
When the men came up they saw an indistinct, woolly mass on the other side of the beck.

The mass was not level but slanted sharply, and the sheep at the bottom sent down showers of stones as they surged to and fro, with heads turned to the dogs.

It was obvious that they did not mean to go down the ghyll, and Herdwicks born among the crags can climb where no dog can follow.
"The dogs canna turn them," gasped Tom.

"They'll be away ower Eel Scar; they're brekkin' noo." The flock began to open out and three or four sheep straggled forward, but Kit's bob-tailed dog slid down a snowy slab and fell upon the first.
The sheep ran back, but the others stood and Kit saw the dog could not stop them long.