About a decade ago a fine-grained, black rock specimen was submitted to the laboratories of the Bureau of Reclamation, U. S. Department of the Interior, Denver, Colorado. The hand specimen had a satin-like luster and conchoidal fracture, giving it the appearance of cannel coal. It came from a complex series of flows and beds of volcanic origin, 6 ½ miles east of Vantage, Washington. According to Dr. Wiliam H. Irwin, who later visited the locality and collected further samples, the rocks of the vicinity show great diversity in color, texture, and structure, and show evidences of significant alteration. He further commented that it is not necessarily possible from examination of a hand specimen to ascertain which rocks are lavas and which are altered tuffs.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.