708 CAMBRIAN BRACHIOPODA. 



(58k) Just below the Middle Cambrian in limestones forming 1 of the Mount "VVhyte formation [Walcott, 1908c, 

 p. 240 (9)]; (57m) about 50 feet (15 m.) below the Middle Cambrian in a siliceous shale correlated with II3 of the Mount 

 Whyte formation on Mount Bosworth [Walcott, 1908f, p. 213]; (57e) about 115 feet (35 m.) below the Middle Cambrian, 

 in limestone correlated with the top of Ic of the Mount AATiyte formation on Mount Bosworth [Walcott, 1908f, p. 213]; 

 (57r and 58s) about 150 feet (46 m.) below the Middle Cambrian, near the base of the limestones forming 3 of the Mount 

 Whyte formation [Walcott, 1908c, p. 241 (10)]; and (35f) about 300 feet (91 m.) below the Middle Cambrian, in the 

 limestone forming 6 of the Mount Whyte formation [Walcott, 1908c, p. 242 (11)]; all on Mount Stephen, just above 

 the tunnel on the north shoulder, 3 miles (4.8 km.) east of Field, British Columbia. 



(57s) About 160 feet (49 m.) below the Middle Cambrian, near the base of the gi-ay oolitic limestone forming lb 

 of the Mount ^Vhyte formation [Walcott, 1908f, p. 212], on Mount Bosworth, north of the Canadian Pacific Railway 

 between Hector and Stephen, on the Continental Divide between British Columbia and Alberta, Canada. 



ACROTRETA SAGITTALIS TRANSVERSA (Hartt). 

 Plate LXXII, figures 1, la-k. 



Obolella transversa Hartt, 1868, Acadian Geology, by Dawson, 2d ed., p. 644. (Characterized.) 



Obolella transversa Hartt, 1878, idem, 3d ed., p. 644. (Copy of preceding reference.) 



Obolella transversa Hartt, Walcott, 1884, Bull. U. S. Geol. Survey No. 10, p. 16, PI. I, figs. 5 and 5a. (Original descrip- 

 tion copied and species discussed. The specimens represented by figs. 5 and 5a are not redrawn in this mono- 

 graph, but better figures of them are given by Walcott, 1891a, PI. LXVIII, figs. 2a and 2c, respectively.) 



lAnnarssonia transversa (Hartt), Walcott, 1885, Am. Jour. Sci., 3d ser., vol. 29, p. 115, figs. 3, 4, 6, and 7, p. 116. (Dis- 

 cussed as the type of the new genus Linnarssonia. Figs. 3 and 7 are drawn from the specimens figured by Wal- 

 cott, 1884a, PI. I, figs. 5 and 5a, respectively.) 



Linnarssonia transversa (Hartt), Matthew, 1886, Trans. Roy. Soc. Canada for 1885, 1st ser., vol. 8, sec. 4, No. 4, p. 35, 

 PI. V, figs. 11, lla-e. (Discussed. Casts of the two specimens represented by figs. 11, lla-e are figured by 

 Walcott, 1891a, PI. LXVIII, figs. 2d and 2a.) 



Obohlla transversa Hartt, 1891, Acadian Geology, by Dawson, 4th ed., p. 644. (Copy of Hartt, 1868, p. 644.) 

 -Linnarssonia sagittalis transversa (Hartt), Walcott, 1891, Tenth Ann. Rept. U. S. Geol. Survey, Description of PI. 

 LXVIII, figs. 2a, 2c, and 2d. (No text reference. Figs. 2a and 2c are drawn from the specimens figured by 

 Walcott, 1884a, PL I, figs. 5 and 5a, respectively. Fig. 2d is drawn from the specimen figured by Walcott, 

 1885a, fig. 6, p. 116. Figs. 2d and 2a are drawn from casts of the two specimens figured by Matthew, 1886, PI. V, 

 figs. 11, lla-e.) 



Linnarssonia transversa (Hartt), Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, 

 PI. Ill, figs. 22 and 23. (Fig. 22 is drawn from the specimen figured by Matthew, 1886, PI. V, fig. 11.) 



Linnarssonia transversa (Hartt), Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 108, PI. 

 Ill, figs. 38-42. (Mentioned in the text. Figs. 38-39 and 40-42 are drawn from the specimens figured by 

 Matthew, 1886, PI. V, figs, lie and 11, respectively. Figs. 42 and 39 are copied from figs. 22 and 23, respectively, 

 of the preceding reference.) 



Linnarssonia transversa (Hartt), Matthew, 1895, Trans. New York Acad. Sci. for 1894-95, vol. 14, p. 125, PI. V, figs, 

 la-c and 2a-c. (Locality mentioned. The figures are copied from Matthew, 1886, PI. V, figs. 11, lla-e.) 



Linnarssonia sagittalis transversa (Hartt), Frech, 1897, Additional plates inserted in 1897 in Lethsea geognostica, pt. 1, 

 Lethsea palseozoica, Atlas, 1876, PI. lA, fig. 3b. (No text reference. Fig. 3b is copied from Walcott, 1891a, PL 

 LXVIII, fig. 2d.) 



This is the representative of Acrotreta sagittalis (Salter) in the Paradoxides zone of New 

 Brunswick. Many shells are more transverse in outline than the average of A. sagittalis, but 

 examples of the latter (PI. LXXI, figs. 3, 3a, 3g, 3j) are nearly as much so and the interior 

 casts show a striking similarity in the Welsh and Acadian forms. The range of variation in 

 each form is nearly as great as the variation between the two. . In view of tliis, I think it is 

 best to characterize transversa as a variety of A. sagittalis. 



The shells from the "Protolenus beds" of Hanford Brook also vary in form from the nearly 

 circular variety magna to .the transverse forms included under transversa. 



Formation and locality. — Upper Cambrian: (3) Shales 300 feet (91.4 m.) above the Paradoxides zone, Manuels 

 Brook, Conception Bay, Newfoundland. 



Middle Cambrian: (2f and 2g) Sandstones of Division Ibl : (21i) overlying 2g in the sandstones of Division lb2; 

 (2) sandstones of Division lb2; (2i) sandstones of Division lb3; (2k) overlying 2i in the sandstones of Division lb3; 

 and (301b) sandstones of Division lb5 and higher; all in Matthew's [1895a, p. 108] Protolenus zone, Hanford Brook, 

 St. John County, New Brunswick. 



(301c) Sandstones of the St. John formation, at Coldbrook; and (301k) St. John formation, in the city of St. John; 

 both in St. John County, New Brunswick. 



