In the course of more than one century of studies of the stony meteorites, chondrules have been frequently described for their morphology, composition and structure, particularly the condrules ranging in size from 0.5 to 1 mrn. Only very few attempts (Ramdohr, 1966;Michel-Levy, 1968) have been made to describe the smaller individuals. The purpose of this paper is to report the results of an investigation of the morphology and composition of chondrules which are less than 250p. in size and are regarded as microchondrules, and to present some conclusions concerning the formation of the chondrules.

A mineralogical and chemical analysis has been performed on the largest mass (8750 g) of the Girgenti, Italy, meteorite, from the collection of the Smithsonian Institution, Washington, D.C. The mineralogical composition is olivine, Fa24–25; hypersthene, Fs21 –22; plagioclase, An12; maskelynite; whitlockite; nickel‐iron; troilite; chromite and ilmenite. Girgenti is a severly metamorphosed stone, whose total iron content (23.5%) is somewhat higher than the average for hypersthene chondrites.

The fall of a meteorite shower in Marilia, Sao Paulo State, Brasil, is announced. An individual specimen is macroscopically described in some detail. The X‐ray diffraction analysis shows it to be an olivine‐bronzite chondrite or group H4 classification.

A chemical analysis and a mineralogical inspection have been performed on about 50 g of the Mafra, Santa Catarina State, Brazil, meteorite. The stone is an H‐4 chondrite. It shows some ambiguous characteristics concerning the iron distribution, which are discussed.

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