The problem of the origin of the anhydrite cap rock, and processes peculiar to it, have been discussed in an earlier paper (Goldman, 1933). The interpretation there presented, which is coming to be the one held by more and more geologists, is that the anhydrite cap rock is formed by the accumulation of anhydrite originally present in the salt stock, freed by the solution of the enclosing salt, and subsequently cemented. The flat surface at the top of the salt stock along which this solution takes place is called the salt table. The anhydrite freed from the salt is of two types: (1) crystals of anhydrite disseminated in the salt, mainly along the dark bands, the so-called “annual layers;” (2) fragments of fine-grained anhydrite rock, generally whiter than the anhydrite that encloses them in the cap rock. Some of these fragments are banded. These, I assume, are parts of sedimentary beds of anhydrite that were in the salt that formed the stock. I call them “primary sedimentary clasts” or merely “clasts”.
When the earlier paper was written I could learn of no trustworthy records of the occurrence of primary, sedimentary anhydrite rock in the salt of American salt stocks (Goldman, 1933, p. 85). However, Hanna (1934, p. 637) has recorded that “A very few larger chunks of anhydrite have been found within the salt” of salt stocks. Later Taylor (1938, p. 93) recorded “knots of finer grained anhydrite that are rather common in the salt” and that “appear to be . . .