France. Service de la carte geologique de France Explanatory text: 1 sheet in MC folder. North Decimal Degree 51.0354 South Decimal Degree 50.5766 East Decimal Degree 1.8817 West Decimal Degree 1.2662 Alternate title: Boulogne-Calais. Relief shown by hachures. Principal meridian: Paris. Longitude is given in centesimal values (100 grades = 90 degrees) .The Service de la carte geologique de la France was integrated to the BRGM to become the only France Service geologique national