```python
from typing import List

def sift_marks(entries: List[str], mark: str) -> List[List[str]]:
    marked_run: List[str] = []
    unmarked_run: List[str] = []
    
    for entry in entries:
        if entry.startswith(mark):
            marked_run.append(entry)
        else:
            unmarked_run.append(entry)
    
    return [marked_run, unmarked_run]
```