Shares of the world's leading provider of geoscience data to oil companies TGS fell by more than 6 percent on Thursday, after disappointing sales in the second quarter. TGS reported $108 million in quarterly revenues, 6 percent below consensus, and compared with $114 million in the second-quarter a year ago. "Part of the problem was that TGS failed to sell more in Brazil, where PGS and CGG did well, or in Mexico, where it had data in the wrong place or it was simply too expensive," Iver Baatvik at ABN-AMRO bank said. The so-called late sales of seismic data were down to $79 million from $84 million a year ago. Peers including Schlumberger, PGS and CGG all reported year-on-year growth in the second quarter.