```ts
export function siftMarks(entries: string[], mark: string): string[][] {
  const markedRun: string[] = [];
  const unmarkedRun: string[] = [];

  for (const entry of entries) {
    if (entry.startsWith(mark)) {
      markedRun.push(entry);
    } else {
      unmarkedRun.push(entry);
    }
  }

  return [markedRun, unmarkedRun];
}
```