G. D. Harris — Tertiary Geology of Maryland. 25 



quadricostata, Nassa peralta, small var., Scala pachypleura,* ISTiso 

 lineata ?*, Pyrula sp. nov., Turritella indenta,* Turritella ex- 

 altata,* Turritella plebeia, Solarium trilineatum, Crucibulum con- 

 strictum, Crepidula, small sp., Natica heros, Natica duplicata, 

 Sigaretus fragilis,* Calliostoma sp., Infundibulum perarmatum,* 

 Fissurella marylandica.* 



Brachiopoda. — Discina acetabula. 



In addition to the above forms, Conrad mentions in the 

 Proceedings of the National Institution, Area depleura, Pectun- 

 euhis lentiformis, Lima papyria, Cancellaria biplicifera^ 

 Dentalium thalloides, Voluta nnitabilis, Marginella jperex- 

 igua, and Trochus peralveatus. Of these, Pectunculus lenti- 

 formis and Voluta mutabilis were afterwards called by Con- 

 rad himself, P. parilis, and V. typus. The name Dentalium 

 thalloides had been applied by this author nine years before to 

 a characteristic Claiborne species. 



Section 6, may be subdivided as follows : 



No. 1. White sandy clay 15 feet. 



2. Light clay with conchoidal fracture. .. 12 " 



3. Yellowish sandy clay 16 " 



4. Zone d y Isocardia bed ; Yellowish sands .. 8 " 



5. Bluish sandy clay 14 " 



6. Zone c y thin seam of Venus sp. nov. and 



sand 6 inches. 



7. Clayey sand ; bluish above, becoming brown- 



ish below 15 feet. 



8. Zone b • greenish gray sands - * 8 " 



The Isocardia of Zone d is quite different from I. fraterna, 

 as well as from I. rustica. It is smaller, not so large poste- 

 riorly, and with differently formed teeth. The new species of 

 Venus which characterizes Zone c, bears some resemblance to 

 V. penita. The same, or a very closely allied species was 

 found by the writer about 1|- miles southeast of Skipton, Tal- 

 bot county, on the " Eastern shore " of Maryland. 



Section 7. — This section presents no very remarkable fea- 

 tures. As seen on map, p. 23, nearly all the component beds 

 of Section 6 are found here from 5 to 8 feet nearer tide level 

 than they are in that section. Before passing on to Section 8, 

 however, it may be remarked that Conrad was doubtless some- 

 what mistaken in giving "Col. Beckett's" as the location of a 

 fossiliferous outcrop ; for the low bluffs all along the old 

 Beckett farm (just above Dare's landing), are made up wholly 

 of Pleistocene sands. 



Section 8. — Just below Parker's creek, on land owned by 

 James Hance, steep escarpments occur ranging in height from 

 40 to 70 feet. In these, Zones c and d are found much nearer 



