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IV. — A Letter from Dr. Harlan, addressed to the President, on the 

 Discovery of the Remains of the Basilosaurus or Zeuglodon. 



[Read January 9, 1839.] 



Mr. President, 



W ITH your permission, and at the request of several Members, I offer a few ob- 

 servations on the fossil bones from the United States now on the table. 



In the early part of the year 1832 a large fossil vertebra was presented to the 

 American Philosophical Society by Judge Bree of Louisiana, found in the "marly" 

 banks of the Washita river, Arkansas territory. We then ventured to consider 

 it as the vertebra of a large extinct Saurian of a nondescript genus, and proposed 

 to name it provisionally Basilosaurus ; the matrix contained a species of fossil 

 Corbula, common in the Alabama tertiary deposits ; — these remarks were not pub- 

 lished until 1834. In the autumn of the same year a box of similar bones was 

 received from the Hon. Mr. Creagh, from his plantation in Alabama, containing 

 several enormous vertebrae, an os humeri, portions of the jaws and teeth, and some 

 other fragments, supposed to belong to the same animal. Specimens of Nautilus, 

 Scutella, and Mo clicks, of extinct and new species, together with some fossil 

 Shark's teeth, were obtained at the same time, from a similar rock in the vicinity. 

 The great disparity in the proportional size of the different bones, which are all 

 destitute of animal matter, presents a remarkable feature in the structure of this 

 animal ; so much so indeed, that we were at first disposed to refer the large and 

 small vertebrge to different species ; and one rib, obtained at the same time, is 

 evidently that of a fossil Manatus. Bearing in view the form and structure of the 

 teeth only, we should have been inclined to have ranked the animal amongst the 

 marine Carnivora, however unlike those organs in any known species ; but a 

 careful examination of the other portions of the skeleton, especially of the lower 

 jaw, which is elongated and hollow, appeared to forbid this arrangement, and to 

 characterize it as a lost genus of the saurian order. The immense size and pro- 

 portions of the vertebrae, and the total length of the vertebral column in the two 

 skeletons — the one noticed at Alabama, the other at Arkansas — being estimated, 



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