- journal_title：Geological Society of America Bulletin
- Contributor：DENIS W ROY ; ROBERT H HANSMAN
- Publisher：Geological Society of America
- Date：1971-
- Format：text/html
- Language：en
- Identifier：10.1130/0016-7606(1971)82[3183:TOOSF]2.0.CO;2
- journal_abbrev：Geological Society of America Bulletin
- issn：0016-7606
- volume：82
- issue：11
- firstpage：3183
Fractured surfaces almost morphologically identical to shatter cones were found in museum specimens of Cambrian shales from two widely different localities: (1) in the Mojave Desert, California (34°35′ N., 115°30′ W.), and (2) in the Avalon Peninsula, Newfoundland (47°32′ N., 52°57′ W.). The cones differ significantly from cone-in-cone, and their observed features do not suggest an organic origin. The cones are very rare in the California locality and no other features that could be interpreted as shock-induced were observed during a recent field visit. The Newfoundland locality has not been re-examined. Evidently shatter-cone-like fractures may be produced in shales by processes unrelated to shock waves.