1847.] ANTHONY ON ORTHOCERAS. 255 



2. Letter from J. G. Anthony to C. Lyell, Esq., V.P.G.S., May 6, 

 1846, ^'On an Impression of the Soft Parts of an OrthocerasT 



Cincinnati, May 1, 1846. 



Dear Sir, — In accordance with the wish expressed by you a 

 short time since, that I should communicate to you some account of 

 the Orthoceratites found in the marlite near Cincinnati, I have thrown 

 together a few brief notes which may perhaps serve as the basis of a 

 paper on the subject. 



The blue limestone formation, of which the marlite above alluded 

 to is a member, was formerly supposed to represent the Trenton 

 limestone of the ''New York system," but further examination has 

 proved its identity with the " Hudson River group." In the State 

 of New York, where it is widely developed, it consists mainly of ar- 

 gillaceous deposits ; but in this section it is quite calcareous, and is 

 composed of alternate layers of a hard fossiliferous limestone and 

 shale, or as it is frequently termed marlite, interstratified and lying 

 horizontally. The thickness of the blue limestone at Cincinnati is 

 about 450 feet. Quarries have for many years been opened in this 

 deposit for the purpose of procuring the hard limestone for build- 

 ing and for paving our streets. In the removal of the stone for 

 these purposes, many beautifully preserved remains of the " Ab- 

 origines of Creation" have been brought to light, and a greater 

 number have been discovered on the hill-sides, where the refuse of 

 the quarries has lain long enough exposed to the action of frosts and 

 washings of heavy rains. 



The layers of which the blue limestone formation is composed are 

 by no means uniform in thickness, the hard stone varying in this 

 respect from one inch to eighteen, and the soft shale from six inches 

 to many feet. Numerous species of fossil shells, Trilobites, Crinoidea, 

 &c., are distributed throughout the entire deposit, the same species 

 generally occurring at various elevations, though it often happens 

 that a certain species may be abundant at certain points and be com- 

 paratively rare or even entirely wanting at others. 



In the spring of 1842 a quarry was opened on the side of the hill, 

 where the Cincinnati Astronomical Observatory has since been erected. 

 In the progress of the work, a deposit of the marlite was reached of 

 an unusual thickness ; this occurred at a point about 200 feet above 

 low-water mark of the Ohio river. This stratum was of a peculiarly 

 fine, soft nature, admirably adapted to preserve the more delicate 

 parts of the imbedded fossils ; and its consistence was such, that it 

 could easily be cut with a knife and the superfluous marl removed 

 from around the fossils, so as to exhibit them in the best possible 

 manner. This matrix afterwards became quite hard in drying, but 

 was always liable to disintegration by moisture, so that fossils could 

 only be preserved in it by protecting the surface with a coat of varnish 

 or glue. This point in the deposit was unusually rich in the fossils 

 commonly found in the blue limestone. These remains consisted of 



Calymene Senaria. Triarthrus Beckii. 



Asaphus, one species. Isoteles megistos. 



Trinucleus Caractaci ? Bellerophon bilobatus. 



T 2 



