Simplify the following text for a Grade 8 native English-speaking person.
Original: The Grampians extend southwest to northeast between the Highland Boundary Fault and Gleann MÃ r ( the Great Glen ) , occupying almost half of the land-area of Scotland .
Simplified: The Grampians extend southwest to northeast between the Highland Boundary Fault and Gleann MÃ r ( the Great Glen ) .