| Description |
[iii], 23 leaves : illustrations |
| Summary |
"The Robideaux [sic] sandstone (Cambrian) which is rather extensively found in the vicinity of Rolla, Mo., offers exceptional opportunities for the study of ripple marks and sun cracks in place. Fig. 1 shows the principal localities in which these structures are to be found in this vicinity. The statement is made by Van Hise and others that ripple marks can be used in determining structures, and that to do this it is necessary to be able to tell whether a ripple mark is right side up or overturned. The rule as laid down by them is: That a normal ripple mark (right side up) has a wide trough separated by two sharp ridges. Having found some ripple marks the converse of this near Rolla in a structure which is not overturned, we have endeavored to determine how often this statement of Van Hise's is true, and if there are other criteria which might be used in the determination"--Introduction, leaf [1]. |
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