Notices of Memoirs — F. A. Bather — Pollieipes, etc. 521 



tliey had been reduced to a compact flinty type in which none of the 

 minerals could be recognized with certainty. Where the original 

 constituents had survived they were of a fragmentary character. 

 Oligoclase seemed to have best resisted the crushing, and orthoclase 

 occasionally remained in lenticles, but the brittle quartz had been 

 invariably reduced to powder. Mr. Mennell thought that the 

 economic aspect of the examination was of considerable importance, 

 for the mines had been shut down several times when the ore had 

 thinned out owing to doubts as to its permanence. From the 

 character of the rocks it was, however, obvious that they occurred 

 in a true ' fissure lode,' and no doubts need be felt as to the con- 

 tinuance of the ore to the limit of workable depths. 



V. — The Geologic Distribution of Pollicipes k^h Scalpellum.^ 

 By F. A. Bather, D.Sc, F.G.S. 



IN a valuable memoir on the " Hudson River Beds near Albany, 

 and their taxonomic equivalents," published as Bulletin of the 

 New York State Museum, No. 42, April, 1901, Dr. Rudolph 

 Ruedemann describes a number of variously shaped valves found 

 in the Upper and Lower Utica Shale of Green Island and Mechanics- 

 ville, N.Y. (p. 578, pi. ii). These he believes to "find their 

 homologues in parts of the capitula of the pedunculate cirriped 

 genera Scalpellum and Pollieipes, notably of the latter. On tbis 

 account the various valves have been united under the caption 

 Pollieipes siluricus, in full consciousness of the enormous gap 

 existing between the appearance of this Lower Siluric type and 

 the next Upper Triassic (Rheetic) representatives of these genera." 

 Confirmation of Dr. Ruedemann's ascription may be derived from 

 the fact that " the enormous gap " does not exist. Early in 1892 

 Dr. C. W. S. Aurivillius " published the descriptions of Pollieipes 

 gignatus from bed e (= Lower Ludlow), F. validus from bed c 

 (= Wenlock Shale), Scalpellum sulcatum, S. variiim, S. granulatum, 

 S. strobiloides, S. procernm, S. cylindi-ieum, and S. fragile, all from 

 bed c, of the island of Gotland. The species of Scalpellum are 

 founded on peduncles, Pollieipes validus is represented by a broken 

 scutum only, but P. signatiis is based on an almost perfect specimen. 

 The occurrence of more than one species of both these genera in 

 the Silurian lends significance to the diversity of form presented 

 by Dr. Ruedemann's specimens. The ornament on his fig. 18 

 most nearly resembles that of P. signatus, while the rostrum, 

 fig. 22, is also not unlike that species. Figs. 16, 17, and 19 may 

 belong to more than one other species, while 24 (with which pre- 

 sumably 25 is to be associated) may belong to a Sealpellum, as 

 Dr. Ruedemann seems to hint. In the circumstances it is specially 

 regrettable that Dr. Ruedemann has selected no one of these specimens 

 as the holotype of Pollieipes siluricus. If he does not do so soon, 

 confusion is pretty certain to arise. 



' Reprinted from Science, July 19th, 1901, p. 112 (n.s., vol. xiv, No. 342). 

 2 Bihang Sveska Vet.-Akad. Handl., xviii, Afd. iv, No. 3. 



