Open the sheets windows and 1 by hide each sheet til you find the one with your coast, Makes sure it is on the correct sheet because every now and then something ends up on a wrong sheet. If it is on the correct sheet unhide the sheets you had hidden and move the the sheet up until it is visible again.
Correction, sorry I misread and you want teh layer below so do step 1 first then for step 2 if needed lower the sheet till the others that you want above it are above it