He acquired a taste for antiquities from his mother. Later on, Crossing explored Tavistock, Coryton, Lydford, Okehampton, and the northern borders of the Moor, as well as South Brent, on its southern verge.
After leaving school at Plymouth, he went to the Independent College at Taunton, and then returned to finish his education at the Mannamead School.
His earliest literary efforts were in the direction of fiction - 'thrilling romances,' composed for the delectation of his school-fellows. His first essay in poetry was at the age of fourteen, when a poem written by him appeared in the pages of Young England, December, 1861.
In 1863 he went for a short coastal voyage to Wales, and gained a liking for the sea; and in 1864 he joined a vessel bound for Canada, and had a narrow escape, nearly being crushed by an iceberg during the night. Returning from this voyage, he took to business pursuits in Plymouth, and then recommenced his Dartmoor explorations.
In 1872 he married and settled down at Brent. In the previous year he began making notes about his rambles, without, however, any systematic arrangement; after his marriage he seems to have become more methodical, and to have decided to write a book descriptive of the moorland district.
He is now considered one of the best authorities on Dartmoor and its antiquities, having made it the subject of his life's work. He was one of the earliest members of the Dartmoor Preservation Association, joining it immediately on its formation.