. Cambrian Brachiopoda. Brachiopoda, Fossil. 510 CAMBRIAN BRACHIOPODA. Observations.—The ventral valves of Lingulella isse have an outline very similar to that of Lingulella pogonipensis (Walcott) and L. acutangula (Roemer) (PI. XVII), but the dorsal valves are more subquadrate in outline, and even the elongate form of the dorsal valve is more obtusely rounded. The species has a considerable vertical distribution in the House Range section. It is first met with 950 feet ( m.) above the Middle Cambrian, and again at the 1,150 ( m.) and 1,400 foot ( m.) horizons. Fragments of a cl
. Cambrian Brachiopoda. Brachiopoda, Fossil. 510 CAMBRIAN BRACHIOPODA. Observations.—The ventral valves of Lingulella isse have an outline very similar to that of Lingulella pogonipensis (Walcott) and L. acutangula (Roemer) (PI. XVII), but the dorsal valves are more subquadrate in outline, and even the elongate form of the dorsal valve is more obtusely rounded. The species has a considerable vertical distribution in the House Range section. It is first met with 950 feet ( m.) above the Middle Cambrian, and again at the 1,150 ( m.) and 1,400 foot ( m.) horizons. Fragments of a closely allied species occur near the summit of the Upper Cambrian, 2,800 feet ( m.) above the Middle Cambrian, and a single dorsal valve was collected from the Weeks limestone of the Middle Cambrian, 650 feet (198 m.) below the base of the Upper Cambrian. If these two somewhat doubtful, but still closely allied, shells are identical the known vertical range of the species is 3,450 feet (1,052 na.), a range that may be compared with that of Obolus mcconnelli (p. 397) and L. desid- erata (p. 493). The original description of the species [Walcott, 1905a, p. 330] referred it to theMiddle Cambrian, but later collections from the House Range section show this reference to have been incorrect, as the associated fauna occurs in the Orr formation 30 miles to the south. Formation and locality.—Upper Cam- brian: (15d)<» Thin-bedded blue limestone near Cave Spring on the east side of the Fish Spring Range, about 4 iniles { hn.) south of the J. J. Thomas ranch; and (33d) tliin-bedded blue limestone from the same horizon as locality No. 15d at the base of the first high point southwest of the J. J. Thomas ranch, on the east side of the Fish Spring Range; both in Juab County, Utah. (30i) 950 feet ( m.) above the Mid- dle Cambrian and 2,450 feet ( m.) below the top of the Upper Cambrian, near the base of the arenaceous shales and limestone form- ing le of the Orr forma
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