In a few minutes my boat had passed nearly the whole length of the Pittsburgh shore, when suddenly, upon looking over my shoulder, I beheld the river covered with an ice-raft, which was passing out of the Alleghany, and which completely blocked the Ohio from shore to shore. French Creek, Oil Creek, and all the other tributaries of the Alleghany, had burst from their icy barriers, thrown off the wintry coat of mail, and were pouring their combined wrath into the Ohio.