After having served the purposes of the survey, all materials collected shall be distributed by the state geologist to the educational institutions of the state in such manner as the commissioner of environment and conservation may determine to be of advantage to the educational interests of the state; provided, that if deemed advisable, the commissioner may first use such portion as may be necessary to establish a permanent exhibit of the natural resources of the state. On the completion or discontinuance of the state geological survey, the commissioner shall cause all records, notes, books, reports, charts, maps, manuscripts, instruments, and other equipment and property of the survey to be placed in charge of a suitable custodian to be held subject to final disposition by the general assembly; provided, that any field or other equipment which the commissioner shall deem undesirable to preserve may be sold as the commissioner may direct and the money turned into the state treasury; and provided further, that the copies of the reports of the survey left on hand for distribution shall be distributed by the custodian in such manner as shall be for the best interest of the people of the state.