How does Rudyard Kipling use imagery in Mrs. Bathurst?

Example of Imagery:

"...the engine trotted us a couple of miles up the line to a bay of drifted sand and a plank-platform half buried in sand not a hundred yards from the edge of the surf. Moulded dunes, whiter than any snow, rolled far inland up a brown and purple valley of splintered rocks and dry scrub. A crowd of Malays hauled at a net beside two blue and green boats on the beach; a picnic party danced and shouted barefoot where a tiny river trickled across the flat, and a circle of dry hills, whose feet were set in sands of silver, locked us in against a seven-coloured sea. At either horn of the bay the railway line, cut just above high water-mark, ran round a shoulder of piled rocks, and disappeared."