James finds the intersection of Harrison and Halsted but that doesn’t narrow his search down to a single sheet. From there, he locates the intersection of Taylor and Morgan. It looks like he will need to find Sheet 79 or 63 since the address is just north of the intersection. James takes note of the sheets surround Sheet 79: 63 to the north, 62 to the northwest, 78 to the west, 95 to the south, and 80 to the east. This way, he won’t have to revisit the key if Sheet 79 is not the sheet he was looking for.