BY PROFESSOR W. J. STEPHENS, M.A., F.G.S. 1121 



and Havvkesbury in a still closer sequence than was before generally 

 recognised. But see Rev. T. Woods, P.L.S. N.S.W , Vol. VIII. 

 Note 3. — Since the preceding paper has been in type, the fossil 

 has been cleared from the matrix in such a manner as to show that 

 it is really a cast or impression of the exterior aspect, and that the 

 interior surface was quite smooth. It follows that its position was 

 upon the left side. 



EXPLANATION OF PLATE XIV. 



The upper figure represents a specimen from a collection of fossils supplied 

 to the University some years ago, by Dr. Krantz, of Bonn, and bears the 

 label " Mastodonsaurus robustus, Qu. ; Keuper sandstein, Gres triassique 

 superieure, Upper Triassic Sandstone. Loc. Stuttgart. " I presume it to 

 be the lateral thoracic plate of the left side, seen from below, with its bony 

 tissue well preserved. The anterior extremity is that towards the left 

 hand, the line along which it met the corresponding plate of the right side 

 being just above the scale of inches, and the exterior angle from which the 

 ribs radiate just below the numerical ticket. The further extension upward 

 towards the right is evidently connected with the plate, but perhaps not 

 actually a portion of it. 



The lower figure represents a similar plate from Biloela or Cockatoo 

 Island, Port Jackson. It is apparently a secondary cast in sandstone, the 

 bone having been replaced by the matrix. But if it is a primary cast, 

 presenting a reversed image of the original structure, it must be regarded 

 as belonging to the right side of the animal. The large holes have been 

 formed by pebbles of shale, which had been embedded behind the plate, 

 and, presumably, dropped out during the rough handling of the block in 

 the processes of quarrying. A portion of the bone is still embedded in the 

 matrix towards the upper right hand corner, but I have not ventured to 

 attempt its release, until the specimen has been carefully examined by 

 others. 



