Cubical crystals of pyrite partly or wholly altered to limonite are to be found in many parts of York County. In fields and along roads between York and Wrightsville they are especially abundant, altho mostly of rather small size, under a centimeter in diameter. On Schump’s Hill, south of York, they reach much greater sizes; the best locality is along a road running west from the York-Baltimore turnpike just south of the York Water Company’s reservoir, about 2½ km. from the center of the city. They vary from 3 mm. to 10 cm. on a side, and even 15 cm. ones have been reported. The writer once saw one picked up which measured 12 by 8 by 5 centimeters This was somewhat distorted, but the moderate-sizes ones are often highly perfect, with smooth or faintly striated faces with equal sides. It is easy to obtain a series of evenly graduated specimens from 5cm. down to a few mm. on a side.