Fossil Leaves from the Waikato District. With a Description of the Coal Measure Series. By W. H. A. Penseler, M.Sc., B.E., A.O.S.M. [Read before the Wellington Philosophical Society, 11th June, 1930; received by Editor, 13th June, 1930; issued separately, 18th November, 1930.] Plates 69-73. Contents. Introduction. Historical Account. Outline of Stratigraphy. Coal Measure Series. Fossils of the Coal Measures. Fossil Leaves. a. Description. b. Discussion. Geological History. Introduction. As a result of mining operations in the Pukemiro Colleries leaf remains were discovered by the writer in the claystone underlying the coal seam, and on subsequent search were found to be fairly commonly distributed in the shaly claystone which in many places forms the roof of the coal. Similar leaves were found in the other mines of the Waikato district. These leaf remains can rarely be observed at outcrops on account of weathering, and they can be obtained in a fresh condition only when, through the necessities of mining, “bottoms have to be lifted,” or the roof “taken down,” or in “stone drives,” etc. Even then the rocks so distrurbed do not invariably contain these fossils. Probably, during the years in which mining operations have been carried on in this district many fossil leaves have been encountered and specimens have been irrecoverably lost through lack of scientific interest on the part of the technical staff of the different colleries. Assistance in the identifications of the fossil leaves collected was rendered by Mr. W. R. B. Oliver, M.Sc., Director of the Dominion Museum, Wellington, to whom the writer extends his thanks. Palaeobotany in New Zealand has been much neglected and therefore comparisons with other fossil leaves were difficult. In assigning a generic name to a leaf its resemblance to recent leaves was the deciding factor, especially because the leaves were all dicotyledonous. The writer acknowledges his indebtedness to the Dominion Laboratory, Wellington, for the analyses on p. 460. The leaves collected by the writer have been lodged with the palaeontological collections of the N.Z. Geological Survey, Wellington.