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



15. Bluish sandy clay 14-1 1 feet. 



16. Zone c / thiii seam of bluish compact sandy 



clay ._ I—I foot. 



17. Bluish clay 8-15 feet. 



18. Zone b ; grayish sand 8-12 " 



This horizon crosses the Patuxent near 

 Benedict. On the ''Eastern shore " it is 

 well represented in marl pits about £ 

 mile south of Skipton. 



19. Light bluish sandy clay, with thin layers of 



Corbula alta, and with casts of Tellina and 

 Yoldia 16-20 " 



20. Zone a ; greenish gray sand, replete with 



Ostrea percrassa, together with a few 

 specimens of Pecten madisonius and P. 

 Humphreysii s 6 inches. 



21. Bluish green sandy clay as at Fair Haven.. 15 feet + 



Total 203-263 feet + 



In this section there are represented three fairly distinct and 

 well defined faunas. These may be enumerated as follows : 



1. The St. Mary' 's fauna ; characterized by such species as.: 



Area idonea, Astarte perplana, Venus alveata, Mactra poude- 

 rosa, Mactra subnasuta, Solen ensiformis, Terebra simplex, Conus 

 diluvianus, Pleurotoma communis, Fusus parilis, Fusus rusticus, 

 Bulliopsis integra, Nassa peralta, Murex acuticostata, Scala ex- 

 pansa, Turritella variabilis. 



2. The Jones' wharf fauna ; characterized by such species 

 as : 



Mytiloconcha incurva, Area elevata, Carditamera producta, 

 Astarte obruta, Crassatella turgidula, Mysia acclinis, Cytherea 

 marylandica, Mya producta, Pauopsea americana, Turritella tere- 

 briformis, Calliostoma Wagneri. 



3. The Plum Point fauna • characterized by such species 

 as: 



Pecten Humphreysi, Area subrostrata, Byssoarca marylandica, 

 Pectunculus parilis, Astarte varians, Astarte exaltata, Crassatella 

 melina, Lucina Foremani, Cardium leptopleura, Corbula elevata, 

 Isocardia Markoei, Venus staminea, Venus latilirata, Pleurotoma 

 marylandica, Pleurotoma bellacrenata, Scala pachypleura, Turri- 

 tella indenta, Turritella exaltata, Solarium trilineatum. 



In concluding, it may be of interest to make a few brief 

 comparisons between these observations and those of earlier 

 writers. 



