We also learned that the great great great grandchildren of those settlers gradually traveled west across the country to get to California on the west coast. However, there were already Chinese immigrants living there! When we looked at a globe we could see that Asians were able to travel east by ship to get to the west coast of America.
One detail the book left out was when did Chinese settlers first arrive in America? If you would like to do extra research on Chinese immigration, there is one article here. Answer in the comments below!