FOOTMARKS IN THE SANDSTONES OF CUMMINGSTONE 99 
middle line. The transverse concavity is least in the middle of the 
scute and greatest at its posterior edge. 
Antero-posteriorly the inner surface is very convex in the middle 
line, its anterior and posterior moieties meeting in a rounded trans- 
verse ridge, which is nearer the anterior than the posterior margin. 
That part of the scute which lies behind this transverse boundary 
is much thicker than that which lies in front of it. None of the 
numerous wide angulated scutes which I have met with have been 
less than two inches in transverse diameter. 
Of the thick angulated scutes to which I have referred, I know 
only the inner faces, and the minimum thickness, as no one of the 
specimens (which are all natural casts) shows the outer face. Again, 
the only specimens I have met with have been associated with re- 
mains belonging to the anterior part of the body, such as the scapula 
or the ribs. 
A cast of one of these, on the same slab with the impressions of 
two scapule, is two inches long in the middle, and has the same 
width at its widest part, but it is not quite square. The side which 
I take to be the inner is nearly straight; and the inner edge, which 
is 24 inches long, appears to have been thick, and serrated for sutural 
union with its fellow. The anterior side measures about 1? inch in 
length, and is somewhat broken, so that its proper contour can hardly 
be made out. The junctions of the internal anterior and posterior 
edges appear to have been sharply angular, while the antero-external 
angle was slightly, and the postero-external angle greatly, rounded 
off. The internal surface is convex from before backwards, concave 
from side to side. 
I have found scutes very similar to these, but smaller, associated 
with the impressions of some ribs. The smallest of these was not 
more than an inch long, and one which had a length of 14 inch was 
fully half an inch thick at its postero-external angle. On the other 
hand, scutes of this kind appear in some cases to have attained a 
width of more than four inches, and a thickness of seven-eighths of 
an inch. 
The irregular angulated scutes (fig. 3) are pentagonal or rhom- 
boidal, the ridge by which they are marked externally projecting so 
far backwards that their posterior margin (4) becomes triangular. 
One of the largest of these had a length of 1 inch by a breadth of 
half an inch, and had a roughly pentagonal! form, its anterior edge 
being slightly convex. Another had a length of 15 inch by a breadth 
of 3ths of an inch, and presented only a very small sculptured sur- 
face close to its anterior margin. In fact, the proportion of the 
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