4 TRANSACTIONS OF THE [ocr. 3, 
is the same with that of the Trilobites and Brachiopods sub- 
mitted to me by Dr. Selwyn, I think Professor Lapworth would 
be far from warranted in asserting that there is nothing in the 
St. John’s Market fauna that reminds us, in the slightest degree, 
of the fauna of Point Levis, and I should expect his identifica- 
tions of the two graptolitic species just cited to prove incorrect. 
Moreover, the Cove Fields and St. John’s Market faune, looking 
at the graptolites of these faunz alone, would appear to be dif- 
ferent, since none of the species from these two localities have 
thus far been shown to be identical. 
With respect to the stratigraphical position of the Norman’s 
Kill graptolitic slates (which Professor Lapworth thinks have 
been referred with scarcely a shadow of paleontological evidence 
to the Lorraine or Hudson River group) in the Lower Silurian, 
many interesting facts having a bearing upon this question, that 
have come under the writer’s observation during the past eighteen 
years, might here be mentioned; but I shall limit myself in the 
present paper to the presentation of the following: In the vicin- 
ity of Schodack Landing, and at several other points in the 
northwestern portion of Columbia and the southwestern portion 
of Rensselaer counties, New York, the Norman’s Kill graptolitic 
zone, here about fifteen feet in thickness, is excellently exposed; 
and has yielded, in addition to fifteen of the Norman’s Kill 
species, a smal] Lingula, and a Lamellibranch probably identical 
with the Lyrodesma pulchella of Hall (Pal. N. Y., vol. 1, p. 302, 
pl. 82, Fig. 12). Thestratigraphical position of this zone, judg- 
ing from several good exposures which I have studied in 
Rensselaer and Columbia counties, is at the summit of several 
hundred feet of soft olive shales, and at the base of a series of 
heavy-bedded grits or sandstones, which I am disposed to look 
upon as the equivalents, respectively, of the Lorraine shales and 
sandstones of northern New York. The gritty beds in question 
have yielded specimens of Orthis testudinaria and Leptena 
sericea, and in the Poughkeepsie Lorraine grits these are often 
the only species present. Moreover, the slates of the locality 
whence the Lyrodesma pulchella was originally obtained (Cohoes 
Falls), abound in specimens of 7rinucleus concentricus. A band 
of graptolitic slates, which I consider probably identical with 
that of Norman’s Kill, also occurs opposite Albany, at a 
point known as Greenbush Heights; although the rocks at this 
point are much altered, and none,of the species which they have 
afforded have been certainly identified. Three-quarters of a mile 
east of the last-mentioned locality, slates similar to those of 
Greenbush Heights are again exposed, and form the greater por- 
tion of a quite prominent elevation known as ‘‘ Cantonment 
Hill.” The slates of this hill (regarded as ‘‘'Taconic” by Dr. 
