DESCRIPTION OF SPECIES 239 



Reticularia pseuclolineata (Hall) 



These specimens are very similar to those from the type locality at 

 Keokuk, Iowa. One pedicle valve measured 36 millimeters wide and 26 

 millimeters long. The spinose ridges are pronounced. The median sinus 

 of the pedicle valve is somewhat more pronounced than the median fold 

 of the opposite valve, but both are broad and but slightly developed, dis- 

 appearing toward the beak. 



Kange. — Burlington to Keokuk of Indiana, Illinois, Iowa, Missouri. 

 At Lake Minnewanka it is common in the upper portion of the Lower- 

 Banff shale. 



PENNSYLVANIAN 

 Spirifer rockymontanus Marcou 



The Lake Minnewanka specimens are in close agreement with those 

 described and figured by White from Utah and New Mexico. 8 



The usual transverse diameter of the Canadian specimens is about 30 

 millimeters. There are about 10 well marked simple plications on each 

 side of the fold and sinus ; there are four on the fold, sprung by dichoto- 

 mizing from the original single plication at the beak. The hinge ex- 

 tremities are rounded and the hinge in most instances is slightly shorter 

 than the width of the shell below. There seems to be a close affinity be- 

 tween 8. rockymontanus and 8. centronatu*. While typical examples of 

 the species are easily distinguished from each other, certain other ex- 

 amples are not so easily distinguishable. 8, rockymontanus is usually 

 larger, with rounded hinge extremities, and its ornamentation has a 

 much coarser aspect, owing to the coarser and sharper plications and 

 their smaller number both on fold and sinus and on the lateral slopes. 

 There is likewise apparently no tendency toward the breadth and promi- 

 nence of the bounding plications of the sinus seen so characteristically in 

 S. albapinensis and persisting to an occasionally obvious degree in 8. cen- 

 tronatus. 



Eange. — Widely distributed in the Pennsylvanian from Ohio and West 

 Virginia to New Mexico, Utah, and Colorado. At Lake Minnewanka the 

 most common Spirifer of the upper portion of the Upper Banff limestone, 

 though never occurring in very great abundance 1 . 



Spirifer camerattis Morton 

 The specimens from Lake Minnewanka arc poorly preserved, but the 



8 Geology of the 10()th meridian, vol. 4. p. 184, pi. LI, Ogs. 9a, b, c, d. 



