. Annual report. New York State Museum; Science; Science. GRAPTOLITES OF NEW YORK, PART 2 53 DOO c \n an initial width of i mm to a maximum width of which is attained in a distance of 15 mm from the sicular extremity and then maintained. Sicula not observed. Sicular extremity furnished with a short blunt virgella (about .4 mm long) and two equally short straight lateral spines. Thecae numbering 11 to 13 in 10 mm (30-32 in 1 inch), inclined at an angle of 300—400, overlapping a little more than one third, the outer margin dis- tinctly convex with the proximal part frequently slightly concav
. Annual report. New York State Museum; Science; Science. GRAPTOLITES OF NEW YORK, PART 2 53 DOO c \n an initial width of i mm to a maximum width of which is attained in a distance of 15 mm from the sicular extremity and then maintained. Sicula not observed. Sicular extremity furnished with a short blunt virgella (about .4 mm long) and two equally short straight lateral spines. Thecae numbering 11 to 13 in 10 mm (30-32 in 1 inch), inclined at an angle of 300—400, overlapping a little more than one third, the outer margin dis- tinctly convex with the proximal part frequently slightly concave, rr*^ The aperture horizontal, concave, the interthecal excavation about one fourth the width. Nemacaulus very thin and inconspicuous y J. within the rhabdosome and not seen protruding beyond the antisicular end. Position and locality. In the transition beds at Van Schaick island (with Cryptogr. tricomis), in the Utica and Lorraine shales of the Hudson, Mohawk and Black river regions. Remarks. This mutation of D. folia- ceus is in the form of the rhabdosome and the form and close arrangement of the thecae most nearly related to D . f o 1 i a c e u s var. acutus and quite evidently a direct descendant of the same. It is the last representative of the group of D. foliaceus in our rocks and persists into the Lorraine beds. In the beds at Van Fig. 2g6-g8 Diplograptus foliaceus Schaick island, which may be properly referable Z'^^l^iliThJll; %£& . ... (Ward's lane), (x £) Fig. 298 Enlargement tO tile Upper DlCellOPTaptUS ZOne, It IS the mOSt (x5)°f one of the rhabdosomes in the group, 11 01 ' reproduced by Hall m plate 72, ngure ia common graptolite and there it attains its maxi- mum size [296]. In smaller individuals it fills layers of the Utica shale, as in the neighborhood of Amsterdam in the Mohawk valley. It further occurs in the uppermost Utica beds around Albany, as at Ward's lane, Black rock, etc. and in the Lorraine beds, whence Hall's type of D . prist is [pi. 72
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