PAST AND PRESENT INTERPRETATIONS. 11 



Carolina. In the absence of evidence to the contrary it would seem proper to extend the 

 application of the name still farther south to include the apparently continuous deposits in 

 South Carolina, Georgia, and Alabama. 



Until recently no organic remains had been found in the beds under discussion south of 

 the Virginia line, but in the fall of 1910 the writer discovered a few poorly preserved plant 

 remains in beds exposed in a bluff on Tallapoosa Eiver at Old Fort Decatur, in Macon County, 

 Ala. These have been submitted to E. W. Berry, who expresses the opinion that the beds con- 

 taining them are of Lower Cretaceous age. One poorly preserved cast of a Unio was found 

 associated with the plant remains. 



The previous conclusions regarding the age of the beds below the Eutaw formation seem 

 thus to be confirmed by the paleontologic evidence. Unfortunately the poorly preserved con- 

 dition of the leaves renders it difficult to determine satisfactorily the relation of the formation 

 to the Patuxent formation of Virginia and Maryland. However, in Berry's opinion, the 

 presence of large numbers of leaves, apparently dicotyledons, most of which are too poorly 

 preserved to permit specific or even generic determination, seems to justify doubt as to their 

 being as old as the Patuxent, in which similar questionably identified dicotyledons are very 

 sparingly represented. 



The following statement concerning the fossil remains of the Patuxent formation is quoted 

 from a paper by Clark and Bibbins: * 



The flora of the Patuxent formation includes Equiseta, ferns, cycads, conifers, monocotyledons, and a very few 

 archaic dicotyledons, the coniferous and cycadean element being particularly strong. The known fauna of the 

 Patuxent formation is limited to a single Unio (Ward) and a fish (Fontaine). 



Should future discoveries confirm the doubt expressed by Berry as to the Patuxent age of 

 the Lower Cretaceous beds of Alabama and Georgia, and should it be found that the Alabama- 

 Georgia Lower Cretaceous deposits are synchronous with the "Cape Fear" formation, it would 

 at once become apparent that the name Patuxent was not appropriate for Lower Cretaceous 

 deposits anywhere south of Virginia. 



Although the "Cape Fear beds" appear to be continuous with the Lower Cretaceous arkosic 

 beds of South Carolina, Georgia, and Alabama, it is possible that they are not actually con- 

 tinuous; for the irregular character of the bedding, the presence of numerous local unconformi- 

 ties within the beds, and the lack of extensive exposures render the detection of an important 

 unconformity difficult — and such an unconformity may exist. 



A hypothesis which was suggested to the writer by T. W. Vaughan and which is worthy of 

 consideration is that the arkosic beds extending from Maryland southward to Alabama were 

 laid down along a coast margin which was being gradually and continuously depressed from the 

 north to the south. In this case the deposits might actually be continuous and yet contain 

 fossil plants at the south end of the belt of outcrop younger than those at the north end. 



UPPER CRETACEOUS. 



EARLY CORRELATIONS. 



Morton's correlation. — The presence in the eastern Gulf region of the so-called "Ferruginous 

 sand formation" was first noted by Morton 2 in 1829, the beds thus designated being correlated 

 with the "Ferruginous sand formation" of New Jersey and with the Chalk of Europe, espe- 

 cially with the Ferruginous sand of the English geologists and with the Lower Chalk of the 

 French geologists. The term Cretaceous, which later supplanted the terms "Chalk" and 

 "Ferruginous sand," was first applied to the American deposits by Morton 3 hi 1S33. 



1 Clark, W. B., and Bibbins, Arthur, Geology of the Potomac group in the middle Atlantic slope: Bull. Geol. Soc. America, vol. 13, 1902, p. 192. 



2 Morton, S. G., Description of two new species of fossU shells of the genera Scaphites and Crepidula, with some observations on the ferruginous 

 sand, plastic clay, and upper marine formations of the United States: Jour. Acad. Nat. Sci., vol. 6, 1S92, pp. 107-129 (especially p. 127). 



3 Morton, S. G., Synopsis of the organic remains of the Ferruginous sand formation of the United States: Am. Jour. Sci., 1st ser., vol. 24, 1S33, 

 pp. 12S-132. 



