This paper presents the results of refraction studies carried out in Pitanga's structural dome, located between Rio Claro and Piracicaba city, NE São Paulo State. The refraction section has approximately 14,100m length with twelve set of geophones-records. The seismic sources were the quarry explosion located at extremities of the section, in two mines of non-metallic minerals. The results of tomographic and plus-minus interpretation show that in the area has a high of basement between 1,000 and 4,000 m from Bonança mine, they also show a large body of diabase near Stavias mine. This structural high may have been done by the compressive stress caused by basic intrusion. This may also have lifted the sediment column exposing ancient sediments.