. Annual report. New York State Museum; Science; Science. Position and localities. Common in some layers at the Normanskill (Kenwood) and at Glenmont near Albany, at Mt Moreno near Hudson, Stockport, Columbia co., Lansing-burg, Rensselaer co. and other outcrops of the Normanskill shale. It has further been recognized by Lapworth in beds of Kicking Horse (Wapta) Pass (Rocky mountains of Canada), which are considered as of some- what older age than the Normanskill shale ; and by the writer in collections of probably like age from Silver Peak Quad- rangle, Nevada. Gurley has found it in shales of
. Annual report. New York State Museum; Science; Science. Position and localities. Common in some layers at the Normanskill (Kenwood) and at Glenmont near Albany, at Mt Moreno near Hudson, Stockport, Columbia co., Lansing-burg, Rensselaer co. and other outcrops of the Normanskill shale. It has further been recognized by Lapworth in beds of Kicking Horse (Wapta) Pass (Rocky mountains of Canada), which are considered as of some- what older age than the Normanskill shale ; and by the writer in collections of probably like age from Silver Peak Quad- rangle, Nevada. Gurley has found it in shales of Normanskill age from Arkansas. Ami has doubtfully referred forms from the neighborhood of Quebec to D . angusti- f o 1 i u s and the present writer identified it in shales from New Jersey. In Great Britain, Lapworth has recorded it as one of the forms of the Glenkiln shales. D . angustifolius had hence a very wide distribution and was common to both the Atlantic and Pacific basins. I am not aware that it rises here above the Normanskill shale. Remarks. Hall says of this species: " The form and proportions of these den- ticles are different from those of any species of graptolite in the collections from these shales, and often more resembling the minute denticulations on the fronds of fossil ferns than those of the ; This peculiar form of the thecae which is well reproduced in the original drawings [see text fig. 311] and is very characteristic of the species, is largely due to the deep excavation of the outer wall of the proximal part of the thecae and the resulting entering of thin shale films between this excavated part of the theca and the preceding theca, whereby the thecae. 312 Dip] ograp t u s angustifolius (Hall). Fig. 311 Copies of Hall's original figures. Fig. 312 Sicular extremity of a rhabdosome x 7. Pig. 313 Portion of a typical rhabdosome from Glenmont. Fig. 314 Specimen from Lansingburg, N. Y. x 5. Please note that these images ar
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