THE NATIONAL INSTITUTION. 183 



of the tide. Over these is a stratum of sand tea feet tliick, in which the same 

 shell abounds. To this succeeds the group most characteristic of these tertiary de- 

 posits, imbedded in sand, the prevalent species consisting of ^rtewi* ocetaiuZwm, 

 a large Venus, Cylherea Suyaiia, C. Marylandica, Corbula idonea, C. cuneata, and 

 Pecten Madisonius. A fine large Mactra, M. ponderosa, which abounds on St. 

 Mary's river, occurs here, but is rare. The univalves are, Fulgur coronatus, F. 

 fusiformis, Fusus parilis, F. cineieiis, Buccinum trivittattim, and B. lunatuin. Tlie 

 last three species, as well as Artemis acetabulum, are living on the Atlantic coast. 

 The large Balanus proteus is abundant. Above this fossilliferous sand is a mixture 

 of sand and clay, without organic remains. Proceeding along the sliorc, we soon lose 

 sight of the Turritella;, and Pectcu Madisonius makes its appearance in great abun- 

 dance. The shells here are higlily ferruginous, as much so as many of the crag, 

 fossils of Great Britain, which they greatly resemble, also, in other respects. Fer- 

 ruginous masses, which have fallen from the cliffs above and mingled with the 

 wreck of pine trees, greatly impeded our progress along the shore. These indurated 

 fragments cover the beach for some miles, and are full of fossils, among which the 

 large Pectens are most conspicuous. From the cliff, in the vicinity of Cove Point, 

 Mr. Markoe was fortunate enough to obtain, through the assistance of Dr. Tongue, 

 a large skull and upper jaw of a new species of Delphinus. Dr. Wyvill, the keeper 

 of the liglit-house at Cove Point, furnished us with an interesting history of Cove 

 Point, by which it appears that the bay has made rapid inroads on the north, and 

 extensive deposition of sand on the south. Indeed, the light-house is now in immi- 

 nent danger of being undermined, and appeared to us to demand the immediate 

 attention of the Government, to save it from being swept away. 



While on the subject of the geology of Calvert, I will notice a locality on the 

 estate of Mr. George Wilkinson, at lluntingtown, in the northern part of tlie 

 county, three or four miles from the Patuxent, to whom we are indebted for every 

 assistance, and for hospitality, for which Calvert county is proverbial. In a de- 

 pression or small valley, Mr. Wilkinson has excavated a race-way through the fos- 

 silliferous " marls," which presents the following section : 



2. Blue marl, with shells similar to the group at Captain Hance's. 

 1. Quartzoso sand, with casts of Perna maxillata. 

 The fossils observed here are the following species : A new Balanus, B. incile. 

 Bivalves. — Area dipleura, Corbula idonea, (Conrad,) Crassatella melina, (Con- 

 rad,) Ostrea percrassa, (Conrad,) Pecten Humphreysii, (Conrad,) P. Madisonius, 

 (Say.,) Pholas ovalis, (Say.,) Perna maxillata, (Lam.,) Orbicula lugubris, (Con- 

 rad,) Pectunculus lentifomiis, Venus staminoa, (Conrad.) 



Univalves. — Bonellia lineata, (Conrad,) Fissurella marylandica, (Conrad,) Pleu- 



rotoma , (new,) Trochus peralveatus, (Conrad,) Turritella indenta, (Conrad.) 



Coral. — Madrepora palmata, (Goldfuss.) 



Three miles from Mr. Wilkinson's, in the bottom of a ravine, great numbers of 

 Perna maxillata and Orbicula lugubris, are imbedded in lead-colored clay. About 

 one mile from this, I observed tho following species : Crassatella marylandica, Coi- 

 bula idonea, Cytherea marylandica, Astarto obruta, Ostrea percrassa. 



Dr. Granger Tongue having proposed a visit to St. Leonard's creek, we coasted, 

 in a small sloop, up the Patuxent, from near Point Patience to tho mouth of the 

 creek. This point is a remarkable spot, extending in a gradually tapering tongujo 



