LIASSIC FORMATIONS. 
21 
mentous attachments of the vertebrae and of their elements, they have yielded to 
external pressure or movement of the matrix, and have rotated on their axis^ — some 
of the long-spined vertebrae to the right, some to the left — with a slight displacement 
of the longer ribs from their attachments. 
The third cervical vertebra is displaced about three inches below the axis and 
atlas, which remain in connection with the occipital tubercles, the third to the 
fifteenth cervicals are prone with the spines uppermost, and the pleurapophyses in 
natural connection with the sides of the centrum, the lower part of which is buried 
in the matrix. Except a slight dislocation between the seventh and eighth, these 
cervicals have retained their natural sequence and relative position. As the spines 
grew longer and larger they offered a surface upon which the superincumbent 
pressure could operate, so as to rotate the vertebrae sideways ; and from the sixteenth 
to the twenty-eighth inclusive, they are turned half round, with the spines downward 
or to the left ; but all these vertebrae retain their natural mutual connections. The 
twenty-ninth vertebra is dislocated, exposing the anterior articular surface of the 
centrum ; the thirtieth has suffered fracture of its spine ; the thirty-first and thirty- 
second are partly bent to the left ; the thirty-third and thirty-fourth are turned with 
the spines to the right side ; that of the thirty-fifth is broken from its neural arch ; 
the thirty-sixth to the forty-eighth vertebrae have the neural spines turned to the right, 
retaining almost their natural relative positions. The forty-ninth vertebra has kept 
the original prone position, as when imbedded ; the next ten show the side view, with 
the neural spines to the right; the sixty-first to the sixty-fifth are prone, but with a 
slight deviation of the neural spines, some to the right, some to the left ; the next six 
vertebrae have yielded in the opposite direction ; there is then a deeper space, equal 
to the extent of five vertebrae, in which there are the centrums of three vertebrae and 
some haem apophyses irregularly scattered. Beyond this part the terminal caudal 
vertebrae resume their position and natural connections, and are preserved, seven in 
number, to the last. The antecedent exceptional violence shown in the caudal series 
has probably been due to the tugging and gnawing of some predatory animal, whilst 
this part of the dead and partly decomposed Plesiosaur eontiiiued to be exposed at the 
sea-bottom. 
The seapulae (51) and articular ends of the coracoids (52) appear parallel with the 
twenty-fifth to the twenty-seventh vertebrae, the left being rather further back than 
the right. Both humeri (53) have been dislocated at the shoulder-joint by super- 
incumbent pressure, and the articular ends of the scapulae overlap their heads. The 
rest of the bones of the pectoral fins have retained their natural relative position, 
protected by the tough, closely-fitting dermal sheath, until this slowly dissolved away. 
The iliac bones ( 62 ) lie by the sides of the forty-seventh to the fiftieth vertebrae, 
almost in the axis of the spine, with their proximal ends turned backward, and their 
acetabular end forward, having become detached from the thick, converging pleura- 
