Abstract
The Organ Mountains lie on the east side of the Rio Grande in Southern New Mexico, east of the town of Las Cruces. During 1933–1935 they were the object of a field study, the results of which will shortly appear.1 In the course of mapping the Tertiary batholith from which the most spectacular part of the range has been carved, several groups of large accidental xenoliths were discovered, among which the most interesting proved to be those situated near South Canyon on the east side of the mountains, 15 miles by desert road south of San Agustin Pass. The present note is concerned mainly with the geology and mineralogy of these xenoliths, which are of special interest to mineralogists because of the presence in some of them of well-crystallized green diopside, associated with the chrome-garnet uvarovite.
