The Intumescens Fauna. — Clarke. 89 
marked with an asterisk) as have appeared in the faunas of the 
Hamilton series, continue their existence to a still later period and 
they, together with Xi<««?i'c«rcZij«?i sp. nov. , Cardiola Doris, and 
C. retrostriata, constitute an association which is emphasized in 
the more abundantly developed faunas of the Styliola lajer and 
the Naples beds. 
Exceedingl}' interesting is the occurrence of a form of Chonetes 
which it is difficult to separate from Chonetes aurora Hall, a form 
known in New York onlj' in the fauna of the Tully limestone, to 
which reference will subsequently be made. 
Above the most densel}" bituminous layers of the Genesee shales 
and near the middle of the series, occurs the stratum which has 
alread}' been termed the Styliola layer:* a bituminous limestone 
but a few inches in thickness, often compact, sometimes of a sub- 
crj'stalline and loose texture, at others inclined to be shaly or 
actually passing into thin chocolate-colored shales, nevertheless 
persistent over an east and west strike of at least 20 miles. It is 
essentially an accumulation of millions upon millions of the minute 
pteropod shell known as Styliola or Styliolina fissurella Hall.^ 
Onh' in a few places does this fossil appear to have given wa}- to 
an inorganic argillaceous calcareous matrix.^ The fauna of this 
laj^er is an assemblage of species, some of which occur in the 
Genesee shales above and below, but many of them appear here for 
the first time. The following list, though incomplete on account 
of including several important undescribed species, is still suffi- 
ciently full to serve our present purpose : 
Dinicthys newherryi Clarke. 
Palieonlscus cZcuouicu.s Clarke, (also in the Naples beds). 
Undetermined plates and scales of fishes. 
Conodonts, (not common, but similar in form to those below, and in 
the Naples beds above). 
*See Bull. U. S. Geological Survey, No. 16 and Neues Jahrbuch fiir 
Mineral. 1891. Bnd. 1. 
^For a figure of a thin section of this pferopodal limestone, see Nich- 
olson and Lydekkcr's Manual of Palaeontology, vol. 1, page 24, fig. 8. 
1889. This illustration docs not show the interesting effects prodiiced 
by the crystallization and cleavage of the calcite, which are referred to 
in Bulletin No. Ki. 
^The position of this layer is just above the heavy bituminous beds 
and not far from the middle of tlie series. In the Bell's gnlly section 
the lower arenaceous shales are thin and contain stragglers from the 
Hamilton mollusean and crustacean fauna with a great abundance of 
LeiorJiyncliits qNadricoatatus. They are about 15 feet in thickness, the 
overlying heavy bituminousbeds having a thicknessof 113 feet. Above the 
Styliolu layer there are 85 feet of the more sandy black shales overlaid 
by the green shales and thin sandstones of the Naples beds. 
