Classical Mythology/Reading/Pausanias 8.8.2
Author:Pausanias
The following story is told by the Arcadians. When Rhea had given birth to Poseidon, she laid him in a flock for him to live there with the lambs, and the spring too received its name, "Lamb Spring", just because the lambs pastured around it. Rhea, it is said, declared to Kronos that she had given birth to a horse, and gave him a foal to swallow instead of the child, just as later she gave him in place of Zeus a stone wrapped up in swaddling clothes.
When I began to write my history I was inclined to count these legends as foolishness, but on getting as far as Arcadia I grew to hold a more thoughtful view of them, which is this. In the days of old those Greeks who were considered wise spoke their sayings not straight out but in riddles, and so the legends about Kronos I conjectured to be one sort of Greek wisdom. In matters of divinity, therefore, I shall adopt the received tradition. Therefore the things said about Kronos I guess to be some wisdom of the Greeks.
Pausanias, Geography of Greece 8.8.2-3
Links to Pausanias The Description of Greece in English Translation.