Pausanias Description of Greece 6.21.3

[3] On the other side of the Cladeus is the grave of Oenomaus, a mound of earth with a stone wall built round it, and above the tomb are ruins of buildings in which Oenomaus is said to have stabled his mares.
  The boundaries which now separate Arcadia and Elis originally separated Arcadia from Pisa , and are thus situated. On crossing the river Erymanthus at what is called the ridge of Saurus are the tomb of Saurus and a sanctuary of Heracles, now in ruins. The story is that Saurus used to do mischief to travellers and to dwellers in the neighborhood until he received his punishment at the hands of Heracles.

[3] On the other side of the Kladeos is the tomb of Oinomaos, a mound of earth with a stone wall built round it, and above the tomb are ruins of buildings in which Oinomaos is said to have stabled his mares. The boundaries which now separate Arcadia and Elis originally separated Arcadia from Pisa, and are thus situated. On crossing the river Erymanthos at what is called the ridge of Saurus are the tomb of Saurus and a sanctuary of Hēraklēs, now in ruins. The story is that Saurus used to do mischief to travelers and to dwellers in the neighborhood until he received his punishment at the hands of Hēraklēs.