. Cambrian Brachiopoda. Brachiopoda, Fossil. FiGUEE 26.â MiCTomitra (,Patcnna) sluarti Walcott. A, A', A", Top, side, and back views of ventral valve, the type specimen (U. S. Nat. Mus. Cat. No. 514S5a). B, B', Top and side of dorsal valve (U. S. Nat. Mus. Cat. No. 514S5b). Tlie specimens represented are from Locality 54n, Middle Cambrian limestones in Blacksmith Fork Can- yon, east of Hyrum, Cache County, Utah. Figures 26A and 26A" are copied from Walcott [190Sd, PI. ^^I, figs. S and Sa]. Dorsal valve ratlier strDtigly convex for a species of this genus; the highest pan is at/ â ala
. Cambrian Brachiopoda. Brachiopoda, Fossil. FiGUEE 26.â MiCTomitra (,Patcnna) sluarti Walcott. A, A', A", Top, side, and back views of ventral valve, the type specimen (U. S. Nat. Mus. Cat. No. 514S5a). B, B', Top and side of dorsal valve (U. S. Nat. Mus. Cat. No. 514S5b). Tlie specimens represented are from Locality 54n, Middle Cambrian limestones in Blacksmith Fork Can- yon, east of Hyrum, Cache County, Utah. Figures 26A and 26A" are copied from Walcott [190Sd, PI. ^^I, figs. S and Sa]. Dorsal valve ratlier strDtigly convex for a species of this genus; the highest pan is at/ â alaout the center of the shell, from whence the slope is very slight to the beak, and rather rapid to the front margin. Beak marginal above a low, broad arching of the posterior mar- gin of the shell; area slio-mi only by a veiy narrow margin where the shell bends toward the naedian line ; no trace of a pseudodel- tidium has been ob- served. Surface marked by narrow, rounded, concentric threadlike striae or ridges with short striae between them. Shell substance corneous. The average size of adult shells is S mm. long by about the same â n^idth. Ohservations.âThis is one of the larger species of the genus. 2Iicrojnitra (Paterina) superba (Walcott) occurs 16 feet ( m.) below and Micromitra (Iphidella) pannula (White) 70 feet ( m.) below in the same section. This fine shell has a short pseudodeltidium much like that of 31. (P.) Jogani (Walcott), but it differs in form and greater size; the same is true of M. (P.) crenistria (Walcott). It may be closelj" related to M. (P.) Jabradorica utahensis (Walcott), but the specimens of the latter are too imperfect for close comparison of foi'm. The specific name is given for my son, Benjamin Stuart Walcott, who assisted me m col- lecting the specimens during the summer of 1906. Formation and locality.âMiddle Cambrian: (54n) About 5-50 feet ( m.) above the Brigham quartzite and 3,640 feet (1, m.) below the Upper Cambri
Size: 3151px × 793px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisherwashi, bookyear1912
