On the receipt of the memorial, the Local Government Board may, if they think a sufficient prima, facie case has been made out, and after requiring (if they think fit) security to be given for any costs which may be incurred by the Board in relation to any local inquiry under this section, direct a local inquiry to be held by an inspector as to the expediency of forming the proposed district and as to the boundaries to be assigned to such district, and as to any further incidental matters in relation thereto as the Board may think fit.