Ireland sheet memoir 156, (Callan) 1858. Descriptions - Sheet 46 NW - illustrating part of the Maps of the GSI. Very good condition.

Ireland sheet memoir 156, Data and Descriptions to accompany Quarter Sheet 46 N.W. of the Maps of the Geological Survey of Ireland. 1858. First edition. 24pp. Paperback. Corners slightly bumped. Manuscript no. 156 at top centre of cover. In little used very good condition.

Geological map 155 is titled Callan and covers the same area as sheet 46 NW. Between 1858 and 1860, the sheet numbering system was revised from quarters of larger notional numbered sheets to a unique number system counting from north to south in rows and west to east in columns. The earlier numbering system was never completed.