Etymology and distribution of 瓜生津.

Uryuudzu 【瓜生津】^{レベル2
About 10}  The Japanese surnames etymology dictionary.

Toukyou-to Hachiouji-shi . Toukyou - to Hachiouji - shi tells Okoshi (oogoe) was the last name. Estimated in the Edo period. There is an example of using a "valley" for a store of a shop name. 大越 Ookoshi reference.