When you talk to The Mayor of Selbina, Abelard, he gives you a lump of Selbina Clay and requests that you to bring imprints of stone monuments from all over Vana'diel left by the explorer Gwynham Ironheart. These are found in all the outdoor areas, not in dungeons.
When a monument is found, trade the clay to the monument to get an imprinted Clay Tablet, and take the tablet back to Abelard.
Get a new piece of Selbina Clay and repeat for the other monuments. There are 17 monuments in total. You can trade them to Albelard in any order; they do not need to be completed in the sequence listed. You will get the Map of the Crawlers' Nest after turning in the first 15 on the list below.
Monument #17 in Batallia Downs requires at least a duo -- one to make the trip through The Eldieme Necropolis, and the other to manipulate the gate switches to open the way to the southward path leading to the Stone Monument's island. Ahtu, the NM killed for the quest The Setting Sun is near the Stone Monument; the walkthrough for that quest describes the route and gate switch order.
You will only receive the map after completing all maps other than Sauromugue Champaign and Batallia Downs. If you complete 15 maps including Sauromugue or Batallia, you will not receive it. The order in which you complete them does not matter.
Go down the gorge at H-7 and head to the eastern tip of the gorge. Go through the cave tunnels, through the next gorge, and through another cave tunnel. Finally head to the end of the next gorge to find the monument at J-7.
Enter Dangruf Wadi through the southwestern corner of South Gustaberg at D-9 and head to the northeasternmost exit at J-3 (you must ride up a geyser and follow the path off the map) into North Gustaberg. Follow the path east. Once you reach the bridge, cross it. Continue until you reach the cave and monument at G-7.