THE NATIONAL INSTITUTION* 
183 
of the tide. Over these is a stratum of sand ten feet thick, 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 Artemiy acetabulum } 
a large Venus, Cytherea Sayana , C. Marylandica, Corbula idonca, 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. cinereus, Buccinum trivittatum , and B. lunatum. The 
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 shore, we soon lose 
sight of the Turritellae, and Pecten Madisonius makes its appearance in great abun¬ 
dance. The shells here are highly 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 light-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 Huntingtown, in the northern part of the 
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. Quartzose 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 melinaj (Con¬ 
rad,) Ostrea percrassa, (Conrad,) Pecten Humphreysii, (Conrad,) P. Madisonius, 
(Say.,) Pholas ovalis, (Say.,) Perna maxillata, (Lam.,) Orbicula lugubris, (Con¬ 
rad,) Pectunculus lentiformis, Venus staminea, (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 the following species ; Crassatella marylandica, Cor¬ 
bula idonea, Cytherea marylandica, Astarte 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 the mouth of the 
creek. This point is a remarkable spot, extending in a gradually tapering tongue 
