The Grand de Tour mosses were found on sandy, limestone, and morainic soils, and on stumps, old logs, and tree bases. They represent 62 sp. from 14 families. The pH of the 2-3 cm. of the soils in which the mosses grew made up the main body of tests, but many tests of soil 1 in. below the surface were also recorded. More than 1100 tests were made April-Nov. under as many different conditions as possible. The limestone soils were all alkaline. The sandy soils had pH values of 3.8-8.2, and the morainic soils of 5.0-85. The pH variations between top soils and the soil 1 in. deep were 0.0-25. Mosses that prefer acid soil are Polytrichum commune, P. piliferum, Catharinea angustata, Pohlia nutans, Dicranum scopariutn, Dicranella hetero-malla, Calliergon schreberi, Hypnum haldanianum, Georgia pellucida, and Bryum caespiticium. Mosses found on soils close to or above the neutral point were Mnium cuspidatum, Bartramia pomijormis, Aulacomnium heterostichum, Brachythecium spp., Anomodon spp., Amblystegium spp., Thuidium recognitum, and Climacium americanum. Mosses seem to have an optimum pH. Most sandy soil mosses are acid although some are alkaline. As in the case of many of the higher plants, some mosses are fairly good soil indicators.