It is no longer necessary to demonstrate the influence of oil contamination on Rolling Contact Fatigue (RCF). Previous studies have shown the consequences induced by the travel of solid particles inside the contacts. In fact, when particles enter the contact, they indent the surfaces. The resulting surface defects, called dents, become stress raisers and increase the risk of spalling and consequently of RCF. In order to compare numerical and experimental results, some tests were performed on a two disk machine with artificially dented surfaces. Cross-sections were performed to complete the surface observations, and to analyse the crack initiation sites and the crack propagation directions. This paper proposes an analysis of these cross-sections to identify the cracks that lead to micro and macro spalling.