12 
PALAEONTOLOGY OF NEW YORK. 
This species may be distinguished from C. monticulatus by the larger size of 
the cells. 
Formation and locality. Lower Helderberg group, Schoharie, N. Y. 
ClLETETES MONTICULATUS. 
PLATE VIII, FIGS. 5-7. 
ChaStetes monticulatus, Hall. Thirty-second Rept. N. Y. State Mus. Nat. Hist., p. 14S. 1S79. 
“ “ “ Report of State Geologist for 1SS2. Expl. pi. 8, figs. 5-7. 1883. 
Coiiallum forming spheroidal masses. Cell tubes polygonal, generally pentago¬ 
nal or hexagonal; diameter from .25 to .35 mm.; walls thin, strongly corru¬ 
gated. Septa slightly thinner than the cell walls, occurring at irregular 
intervals, varying from .33 to 8 mm. or more. On the surface are monticulae, 
arranged in intersecting rows, the centers of which are distant from each 
other about 5 mm., with cells of the same size as on other parts of the surface. 
This species resembles C. colliculatus, but may be distinguished from that 
species by its spheroidal form, and its smaller cell tubes. 
Formation and locality. Lower Helderberg group, Schoharie, N. Y. 
Note. —The two preceding species possess the features usually recognized as characteristic of the 
genus Ciitetetes, but which nevertheless appear to be common to the genus Monotrypa of Ulrich. In the 
present state of our knowledge I propose to leave them, as originally described, under the genus Chtetetes. 
ClEETETES (MONOTRYPELLA) ARBUSCULUS. 
PLATE IX, FIGS, i-3, 6-8, (4, 5) ? 
CJiwtetes fruticosus, Hall. Thirty-second Rept. N. Y. State Mus. Nat. Hist., p. 148. 1879. 
Not Chcetetes fruticosus , Hall. Illustrations of Devonian Fossils, pi. 38, figs. 1-5. 1876. 
Chaetetes fruticosus, Hall. Report of State Geologist for 1882. Expl. pi. 9, figs. 1-8. 18S3. 
Corallum fruticose, several stems arising from a single base; bifurcations 
frequent; branches generally diverging at an angle of about forty-five 
degrees; diameter from 2 to 3 mm. Cell tubes polygonal, arising from, the 
center of the branch and very gradually diverging to the surface; walls 
thin ; exterior smooth or slightly wrinkled transversely. Length of tubules 
