A method for determining the surface areas of stones to enable quantitative density estimates of littoral stonedwelling organisms to be made

1. Surface areas of irregularly shaped stones were determined by coating the stones with a rubber latex solution, removing the mould and calculating the weight of an even film of water which covered the surface of the mould which mirrored the stone surface. 2. Similar work on standard bodies of known surface area revealed that .0020 (± .00012) g of water film covered I cm² of mould. This factor was then used in estimating the surface areas of the stones. 3. It was recognised that this procedure could not be carried out in the field, neither would it be convenient for large repetitive samples so that the possibility of correlating stone surface area with some other parameter which could be more easily measured, was investigated. 4. A relationship was found to exist between surface area and the product of the stones longest length and largest perimeter i.e. y = 2.22 (± .26) x (where y = surface area and x = LP). It was not possible to obtain this relationship by normal least squares method. 5. A sampling procedure based on this technique and using the individual stones as the sampling unit was suggested. 6. The statistical treatment of raw data which would be obtained from such a sample was discussed.