Part II. Paleontology: Introduction
Lithologic criteria alone are inadequate to present a true picture of the southern Appalachian Cambrian stratigraphy. Hitherto most of the fossils collected, except the brachiopods which form a minor element, remained undescribed. A study without illustration of the contained faunas can not give satisfactory concepts of the Cambrian formations. It was hoped that a few illustrations would suffice, but needs which developed during the study required investigation of most of the fossils in hand. At once it was clear that unless the more common and diagnostic species were presented this paper would contribute little beyond a rectification of the nomenclature of the formations. As it now stands there is sufficient information regarding the faunas to make it a brief handbook, which should expedite future work in the region.
Not all the species have been described. Many were left aside for various reasons but mainly because their full study will require years of patient labor.
CRYPTOZOA AND OTHER FORMS
Thus far none of the southern Appalachian rocks of appropriate composition and texture have yielded noncalcareous algae of either the filamentous or the flat type. On the other hand the calcareous forms are profuse. Most of these are the “Girvanella” or Cryptozoon types of structure. As usual, where silicification takes place the Cryptozoa are chosen first, so that when the rock disintegrates they accumulate in the soil. Only one example of the small forms is figured (Pl. 5, fig. 13) because the Cryptozoa are well known. Both the . . .