CC Madhya 15.204

pāka-śālāra dakṣiṇe — dui bhogālaya
eka-ghare śālagrāmera bhoga-sevā haya
Word for word: 
pāka-śālāra dakṣiṇe — on the southern side of the kitchen; dui bhoga-ālaya — two rooms for offering food; eka-ghare — in one room; śālagrāmera — of Lord Śālagrāma; bhoga-sevā — offering of food; haya — there is.
Translation: 
On the southern side of the kitchen were two rooms for offering food, and in one of them the food was offered to Śālagrāma Nārāyaṇa.
Purport: 

Among the followers of the Vedic way, the śālagrāma-śilā, the vigraha of Nārāyaṇa, is worshiped in the form of a stone ball. In India, every brāhmaṇa still worships the śālagrāma-śilā in his home. The vaiśyas and kṣatriyas may also engage in this worship, but it is compulsory in the house of a brāhmaṇa.