G. D. Harris — Tertiary Geology of Maryland. 31 



Conrad,* in 1841, seemed not to detect the true stratigraphy 

 of the fossiliferous deposits he noted along this shore, and 

 strangely enough, apparently believed them to extend nearly 

 horizontally from Fair Haven to Drum point. 



In 1880, Heilprinf concluded from a study of the paleonto- 

 logic literature on the subject, that there must be a southern 

 dip along this shore in so much as two faunas, differing con- 

 siderably in their relative proportions of recent and extinct 

 species, are here represented. To the older fauna, the species 

 occurring at Fair Haven, " Col. Blake's," " Capt. Hance's," 

 and those from the base of the " Cliff near Beckett's," are 

 referred ; to the newer, those from the upper part of the last 

 mentioned cliff as well as those from localities south of Cove 

 point. Had Heilprin examined these sections personally, his 

 conclusions would doubtless have been quite different. The 

 three-foot fossiliferous layer in the upper part of Conrad's 

 section at " Beckett's " is obviously the same as Zone d of the 

 present essay, and not the Jones's wharf beds as Heilprin sup- 

 posed. Nor is it this bed that furnishes the St. Mary's fauna 

 below Cove point : between the two occur at least 70 feet of 

 deposits bearing a well marked fauna. 



In Darton's^: paper on the " Mesozoic and Cenozoic Forma- 

 tions of Eastern Virginia and Maryland," published in 1891, 

 he subdivides the " Chesapeake formation " into three parts, 

 thus : " The lower beds consist mainly of dark-colored clays 

 and fine, mealy sand containing the extensive an.) well-known 

 "diatomaceous deposits. These are succeeded by lighter colored 

 clays and sands, with occasional local inclusions of blue marl. 

 The upper beds are coarse-grained, and consist chiefly of white 

 beach sands containing shells and deposits of shell fragments, 

 and occasional argillaceous members." The outcrops at Her- 

 ring bay are said to belong to the lower beds ; those on the 

 lower St. Mary's river to the medial ; and u those along the 

 lower Patuxent river and the adjoining shores of Chesapeake 

 bay," to the upper beds. 



*2d Bull. Proc. Nat. Inst, 1842, p. 116. 



f Proceed. Phila. Acad. Nat. Sc, 1880, pp. 23-30. 



X Bull. G-eol. Soc. Am., vol. ii, p. 444. 



