We are all familiar with the the rhyme:
Jack and Jill went up the hill.
The preposition 'up' describes motion from a lower level to a higher level. But the preposition 'onto' also describes 'motion'. Therefore, can we use the preposition 'onto' in place of 'up'?
Jack and Jill went onto the hill.
Is it grammatically correct? If correct, is there any difference in meaning?