MIDDLE CAMBRIAN, AT STISSING, N. Y. 107 
acic spinous processes, and the different structure of 
the pygidium. 
It is very desirable that other fossiliferous localities of 
this zone should be found in the county ; but much 
search has so far failed to reveal any such in the immense 
displays of calcareous shales associated with limestones 
in the northern part of Dutchess County. 
EXPLANATION OF PLATE. 
MIDDLE CAMBRIAN FOSSILS FROM STISSING, N. Y. 
Natural size, except where otherwise noted. All are from the cal- 
careous shales, except those represented by figs. 5, 6 and 15, which are 
from the limestones. 
Fig. 1. Hyolithes Billingsi (?), cast of interior, showing three or four 
slight annulations ; the anterior one more prominent than 
the others. 
Fig. 2. Leperditia ebenina, n. sp., enlarged to 2 diameters ; fragment 
of (right?) valve, showing the line of the hinge, and a 
sloping dorsal angle, also the outer belt of minute contigu- 
ous pits, and the inner tract of larger separated pits. The 
ornamentation indicates that the complete carapace must 
have been at least one-sixth longer than the fragment. 
Fig. 3. ZL. ebenina enlarged to 2 diameters: lacking the cardinal mar- 
gin; showing perfectly the peculiar surface-pitting, and 
the ventralifurrow. 
Fig. 4. J. ebenina, interior view of a central fragment of a valve; 
showing the separated tubercles, corresponding to the sep- 
arated pits of the central exterior. 
Enlarged to 2 diameters. 
Fig. 5. Kutorgina}Stissingensis, n.sp., enlarged to 2 diameters ; a natu- 
ral cast of the dorsal valve. 
' Fig. 6. K. Stissingensis ; enlarged to 2 diameters ; ventral valve ; with 
a side view of the elevation. 
Fig. 7. Gutta percha cast of a natural impression of the interior of 
the unbonal region of a -ventral valve, referred to K. 
Stissingensis ; showing a medial septum from which fine 
stric diverge, and muscular impressions, enlarged to 3 di- 
ameters. 
Fig. 8. K. Stissingensis, cardinal view ; showing false area, deltidial 
opening and the rounded edge between the false area and 
the main surface of the valve; enlarged to 2 diameters. 
57 
