7S Notice of the Discovery of the Zygodon. 



is short and thick. Many of the dorsal vertebne are sixteen or eighteen 

 inches long, and upwards of twelve inches in diameter. The transverse 

 processes are from three to six inches long. The spinal and also the la- 

 teral processes are of about the same length. These last three are united 

 at the base, where they form an arch through which the spinal marrow 

 ran. This arch, with the lateral and spinal processes, is easily detached 

 from the main body of the vertebrae- The head is much broken, yet we 

 have portions of both jaws with the teeth inserted in nearly a perfect 

 state. The molar teeth are inserted into separate cavities of the jaw by 

 two long roots. The upper portion of these teeth is somewhat hastate, 

 with large and rather blunt serratures on the lower part of the anterior 

 and posterior margins, as in those of the Iguanodon. The average longer 

 diameter of a section of the molar teeth is about four and a half inches. 

 The anterior teeth have a single root, are sharp-pointed, conical, slightly 

 curved, and laterally compressed ; the transverse section parallel to the 

 base forming an ellipse. The length of the anterior teeth, including the 

 root, is five or six inches, and the longest diameter nearly two inches. 

 The form of the molar teeth is so peculiar that it is impossible to give a 

 correct idea of them without the aid of plates. 



The Zygodon or Basilosaurus was imbedded in a marly limestone soil. 

 The upper portion, to the depth of one or two feet, is a rich black vege- 

 table mould. Beneath this is a yellowish white marl, yielding easily to 

 the mattock, and containing few organic remains. Most of the bones 

 were in this marl from one to six feet beneath the surface. At the depth 

 of about six feet is a green sand or marl resembling the green sand of 

 New Jersey, and containing few organic remains. The vertebral column, 

 as has been before remarked, lay in an almost unbroken series from the 

 head to the extreme tail, and appeared to occupy the place upon which 

 the animal died. The bones are more or less fossilized, having lost nearly 

 all the animal matter, and been penetrated by carbonate of lime. Yet 

 a large portion of their surface retains the smooth and ordinary appear- 

 ance of bone. The enamel of the teeth is also retained. Numerous sharks' 

 teeth and shells are scattered over the surface, or imbedded in the soil. 

 The most common of the fossils are several species of the genera Ostrea, 

 Exogyra, Pecten, Echinus, Conus, and Scutella. The rocks of the im- 

 mediate vicinity are limestone, which is sometimes as white and nearly 

 as soft as chalk, but destitute of flints or organic remains. This variety 

 is often sawed into blocks and used for building chimneys. The rock 

 partly surrounding the field in which our bones were discovered, is a 

 white limestone filled with nummulites. The grey limestone, with more 

 or less organic remains, is the prevailing rock of the immediate neigh- 

 bourhood. These limestones often present an almost perpendicular 

 escarpment of rock, sometimes in the form of little islands, against which 

 the waves of the olden time appear to have dashed. The spot seems 

 once to have been an cstuar}^ or arm of the sea, interspersed with small 

 islands, and here the Zygodon appears to have lived. Bordering the 

 limestone within a mile of this place, is a red sandstone apparently des' 



