Your textbook includes these as types, as a particular type of glacier movement, but you will see that there are as many textbooks that omit it as a type of movement as include it.

你们的课本中将这些分类，作为一种特殊类型的冰川运动，但是你们会发现，将其作为一种冰川运动类型的教科书和忽略这种类型的教科书同样多。