From the train the mail pouch for California was tossed out.

送往加利福尼亚的邮袋从火车上扔了下来。

For a moment William stood thinking, his eyes upon the saddlebags that held the mail pouch, where they lay upon the ground beside the fire.

威廉站在那里想了一会儿，他的眼睛盯着那个装着邮袋的马鞍袋。

Receiving the mail pouch, containing no more than ten pounds of letters, each rider was expected to gallop away to the next relay station and then turn it over to the next rider.

每位骑手收到邮袋（包括不超过10磅的信件）后，都应跑到下一个中继站，然后把邮袋交给下一个骑手。