During this project we tried to show high capability of the SIS scheme for 1D magnetotelluric (MT) sounding data inversion. The scheme transforms the nonlinear problem of estimating layer resistivities and thicknesses into a linear problem of estimating the coefficients of power series of the new response function. We have used this scheme for prospecting conductive structures in southeastern shore of the Caspian Sea. This area is located in the GolestanProvince in northeastern part of Iran at the border with Turkmenistan. Detecting conductive sediments in this area, which are supposed to bear iodine is economically of interest. We provided data from three MT sites and inverted the data by the SIS scheme. According to our results there is a conductive layer in the depths deeper than 600 m at all three sites. We have compared our results with the previous results, also compared the results with the geological witnesses, which accordingly existence of a conductive layer has been proved at about 700 m depth. This conductive layer is proposed to bear iodine in economic meanings.