. Bulletin - New York State Museum. Science. BEEKMANTOWN AND CHAZY FORMATIONS OF CHAM PLAIN BASIN 485 gin by almost the length of the dorsoventral diameter, sides of aper- ture with low crests. Cameras very shallow, the middle depth of the cameras being 4 mm, where the volution has a diameter of 21 mm; 7 mm where the diameter is 34 mm; sutures nearly straight in the early volutions, but developing a high ventral saddle and shallower lateral lobes upon the later whorls. Septa deep, their depth being equal to that of one chamber in the second whorl and equal to that of two chambers in the third
. Bulletin - New York State Museum. Science. BEEKMANTOWN AND CHAZY FORMATIONS OF CHAM PLAIN BASIN 485 gin by almost the length of the dorsoventral diameter, sides of aper- ture with low crests. Cameras very shallow, the middle depth of the cameras being 4 mm, where the volution has a diameter of 21 mm; 7 mm where the diameter is 34 mm; sutures nearly straight in the early volutions, but developing a high ventral saddle and shallower lateral lobes upon the later whorls. Septa deep, their depth being equal to that of one chamber in the second whorl and equal to that of two chambers in the third whorl. Siphuncle large (about one sixth of the diameter), tubular, propio- ventran from an early stage onward. The surface of the first volution marked with strong growth lines; on the second volution appear rounded costae, which pass the sides very obliquely, swinging backward from the line of in- volution toward the abdomen. Where the dorsoventral diameter of the whorl is 35 mm, the distance of the crests of the costae is 10 mm. Both the costae and the concave interspaces bear a sys- tem of strong raised lines, running par- allel to the costae. Position and localities. Not uncom- mon in the lower Chazy (bed B^)of the Valcour section. Billings's original came from the Chazy limestone of the Mingan islands. Hyatt cites it from the " Calciferous of the Mingan islands " and states that there are similar forms in the same horizon in Newfoundland. Whiteaves has lately [1903, p. 120] remarked that Hyatt was in error in placing the species in the Beekmantown formation. Raymond [1902, p. 20] cites a " L i t u i t e s u n d a t u s ( ?)" from the Chazy beds with Maclurea magna at Crown Point, which presumably is a rep- resentative of this species.^ Observations, Since neither Billings nor Hyatt has figured this species and the latter author gives but a short note about the form, identification of our material with the Mingan form had to rest primarily upon a compari
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