Some years ago the writer obtained at the Great Notch trap quarry a 5 x 10 cm. specimen showing an aggregate of small crystals of a dull white color, on a fragment of trap rock. This has recently been submitted to Mr. H. P. Whitlock, of the American Museum of Natural History, who has identified it by blowpipe tests as barite. Altho this mineral is not infrequently associated with trap rocks, and has been found under such circumstances at several other localities in New Jersey, this appears to be the first report of it from this place. At one end of the specimen are a number of very small calcite crystals and a couple of globular crystals of prehnite, but the barite rests directly upon the trap, suggesting that it was one of the earliest minerals to form.