Contained within the 3rd Edition (1957) of the Atlas of Canada is a map that shows two condensed maps illustrating the division of Canada into agricultural regions based on the percentage of total gross farm revenue obtained from a particular source in 1951. The four primary divisions were made according to specific criteria. For Livestock Specialty divisions 70% or more of the gross farm revenue was from sales of livestock and livestock products. This was divided into three subdivisions: Dairy Emphasis, where sales of dairy products made up over 40% of total sales; Cattle Emphasis, where sales of cattle made up over 40% of sales; and General, where neither dairy products or cattle sales represented over 40% of total sales of livestock and livestock products. For Grain Specialty divisions 70% or more of the gross farm revenue was from sales of grain and hay. This was divided into two subdivisions: General, where no single crop acreage exceeded 40% of the total acreage; and Wheat, where the wheat acreage exceeded 40% of the total acreage. For Combination Grain and Livestock divisions less than 70% of the gross farm revenue was from either crops or livestock. This was divided into two subdivisions: Cash Crop Emphasis, where the gross revenue from cash crops and grain exceeded that of livestock; and Livestock Emphasis, where the gross revenue from livestock exceeded that from grain and cash crops. For Special Crops divisions 50% or more of the gross farm revenue was from some special crops. This was divided into three subdivisions: Tobacco or Potatoes, where 50% or more of the gross farm revenue was from sales of tobacco, potatoes or other root crops; Fruits and Vegetables, where 50% or more of the gross farm revenue was from sales of fruits and vegetables; and Forest Products, where 50% or more of the gross farm revenue was from sales of forest products. Variations within the subdivisions were the basis for a further breakdown into 266 regions to each of which a number and name were assigned.