Metes and Bounds v undivided interest

I recently received the following message regarding some minerals i have available to lease. This is for the deep rights as there is already a pooled unit producing.

"We received cursory title back from our broker and we are not showing any interest owned by you in the SW4 of Sec. 4, Block 39 . The only interest we show is an undivided interest in two separate 4-acre tracts described by metes and bounds, which we would not have an interest in leasing. Our offer was made under the assumption that the interest was undivided across the SW4.”