. Annual report. New York State Museum; Science; Science. GRAPTOLITES OF NEW YORK, PART 2 327 they are seen to begin to curve gently inward and approach again at an approximate distance of 150 mm from the point of bifurcation. The length of the sicula has not been observed, but a short, stiff virgella is nearly always present. The first two thecae bear curved lateral spines at the points of flexure. The first two pairs of thecae grow in alter- nate arrangement, the following in single series separated by a septum. The thecae number 8 to 10 in 10 mm (20- 25 in 1 inch), are mm long, and over
. Annual report. New York State Museum; Science; Science. GRAPTOLITES OF NEW YORK, PART 2 327 they are seen to begin to curve gently inward and approach again at an approximate distance of 150 mm from the point of bifurcation. The length of the sicula has not been observed, but a short, stiff virgella is nearly always present. The first two thecae bear curved lateral spines at the points of flexure. The first two pairs of thecae grow in alter- nate arrangement, the following in single series separated by a septum. The thecae number 8 to 10 in 10 mm (20- 25 in 1 inch), are mm long, and overlap one half their length ; their ventral walls are gently convex, the apertural parts strongly introverted and introtorted, contained in and apparently nearly entirely filling round excavations that occupy one third the width of the branch and equal in length more than one half the free part of the thecae. Position and localities. D. ramosus is common in the Normanskill shale at Kenwood and Stockport; it also occurs in the same horizon at the Moordener kill, at Mt Moreno and at several localities about Troy (as at Mt Olympus). In several outcrops, as those of Glenmont and Mt Moreno, it is very rare and replaced by varieties which occur there profusely. It does not seem here to go in its typical form above the Normanskill shale. Gur- ley [1896, p. 71] claims to have observed a much more slender variety in the Upper Dicellograptus zone at Magog, Quebec, while Whitfield [1877, loc. cit~\ and Gurley have cited it from the Utica shale of the Mohawk valley. The Mohawk valley speci- mens were stated by Whitfield to have come from Oxtungo creek. Slabs from that locality covered with specimens of a Dicranograptus are preserved in the State Museum but the latter prove to belong to a spinose mutation [see below]. Freeh [1877, ] has cited it also from Saratoga lake in New York. The only form known to the writer from that locality is D . nicholsoni. D. ramosus has also been found in t
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