Shiva Purana
महाराजोऽथ सगरस्तद्धयान्वेषणाय च॥ स तं देशं तदा पुत्रैः खानयामास सर्वतः ॥ ५१॥
In order to search out the horse, king Sagara caused the country around dug up through his sons.
english translation
mahArAjo'tha sagarastaddhayAnveSaNAya ca॥ sa taM dezaM tadA putraiH khAnayAmAsa sarvataH ॥ 51॥
hk transliteration by Sanscript