Fifty-four samples of calcitic and dolomitic limestone ground by 21 Virginia companies to a fineness whereby not less than 95 percent would pass through a No. 10 sieve were collected and mechanically separated. The cumulative percentage of the material passing sieve Nos. 10, 20, 40, 60, 100, and 140 was recorded to determine if recommendations are justified on the basis of the percentage of ground limestone passing through a single sieve. A recommendation often used by Agronomists is based on all the material passing a No. 10 sieve with none of the finer particles removed. For this recommendation to be reliable, the percentage of material passing No.10 sieve uniformly should also pass the finer sieves uniformly. The analyses of the 54 samples were divided into five grades of fineness by accepting the cumulative percentage passing sieve Nos. 10 and 100 as standards and the grades were compared graphically. A study has been made of the work done by previous investigators in which they established standards for the evaluation of ground limestone on the basis of fineness. Generally, investigators believed that much of the material failing to pass through No. 10 sieve is too coarse to be any value for a number of years after being added to the soil, but the material passing through a No. 100 sieve will exert its maximum effect soon after incorporation with the soil. To crush agricultural limestone much finer than required for all the product to pass a No. 10 sieve is generally considered uneconomical. As a result of this investigation, the following conclusions are presented: Of the 54 samples separated to determine the cumulative percentage passing No. 100 sieve, 2 fell between 0-20 percent, 11 between 20-40 percent, 25 between 40-60 percent, 11 between 60-80 percent, 4 between 80-95 percent, and 1 with 97 percent. Between 95 and 100 percent of each sample passed No. 10 sieve, while the amount that passed No. 100 sieve varied between 16 and 97 percent. Accuracy in evaluating ground limestone on the basis of fineness was increased by knowing the percentage of material that passed No. 100 sieve in addition to the percentage of material that passed No. 10 sieve. / M.S.