France. Service de la carte geologique de France Explanatory text: 1 sheet in MC folder. North Decimal Degree 49.8572 South Decimal Degree 49.4975 East Decimal Degree 2.7823 West Decimal Degree 1.8921 Alternate title: Montdidier. 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. Based on "Carte topograqphique de l'etat major."