OBOLIDiE. 497 



The original description by Salter [Salter and Hicks, 1867, p. 340] is as follows: 



Length fully 2.5 lines. Form ovate-oblong, the front rather obtuse, but not straight edged; the sides nearly 

 parallel; the obtusely pointed beak includes an angle of about 75°. Generally convex, especially down the median 

 area; the sides beveled obliquely; the surface concentrically and very finely striated; the inner surface rather coarsely 

 sulcate concentrically, indicating close ridges or sharp waves of growth upon the outer sm'face (not visible in our 

 specimens). The inner surface (and probably the outer) shows radiating lines (rather coarse ones) over the median 

 area, but not on the sides. 



The pedicle groove is so wide and pyramidal as to open at anangle of 40°; and its edges are so strongly pronounced 

 as to give the appearance of hinge plates. A short median ridge divides this area, and extends but a very short 

 distance. A specimen, apparently of the shorter valve, has also a median line, but fainter and longer. This is 

 uncertain, the specimen being much crushed. 



The foregoing description was followed by a description of a variety named ovalis by 

 Hicks [Salter and Hicks, 1867, p. 341]. It was collected in the Red Rocks of the Menevian 

 group near St. Davids, and the varietal name was given to it on account of the front edge 

 being "rounded oif, and not squared at aU." Davidson [1868, p. 307] stated that he did not 

 consider this character of any importance, as he had before him specnnens of L. ferruginea 

 of a similar size which had the front quite as much rounded off. Davidson [1868, p. 307] also 

 states that there can be no doubt as to the shell termed LinguleUa unguiculus by Salter in 1865 

 being the same species as L. ferruginea described in 1867. He also states that it is true that 

 L. ferruginea, like most of its congeners, varies slightly in its shape in different examples; some 

 having their front and middle more rounded than others, and the posterior portion converging 

 rather more in some individuals than in others. 



Davidson [1871, p. 336] further observes that — 



this small species has been correctly described and illustrated by Mr. Salter; and is, as far as we are aware, the earliest 

 brachiopod hitherto discovered; for specimens [Davidson, 1871, PL XLIX, fig. 35] were found by Hicks at the middle 

 and the very base of the pm-ple and red rocks of Sedgwick's "Hai-lech group," which dhectly underlies the "Menevian 

 group" or lowest Lingula flags. The position is about 1,200 feet (365.8 m.) lower in the series than the specimen 

 described by Salter and Hicks [1867, p. 340]. The shell does not appear to be scarce, but the beds are much cleaved, 

 and their color is not in any way favorable to the exhibition of the characters of so thin a shell. 



In my remarks [1884a, p. 15] upon the species "Lingula ? dawsoni" Matthew, I called atten- 

 tion to the close resemblance between that species and LinguleUa ferruginea, and said that 

 with only a specimen of the ventral valve for comparison it was difficult satisfactorily to 

 determine the specific relations of the species. 



With the large collections now before me from Newfoundland, and Matthew's and our 

 own specimens from New Brunswick, it is possible to refer the form that has been described 

 as Lingula? dawsoni to LinguleUa ferruginea. 



Before making comparisons between the American and Welsh representatives of the 

 species described, I wiU quote the original description of L. dawsoni [Walcott, 1884a, p. 15], 

 and add such additional data as the specimens from the other collections of Newfoundland 

 have afforded: 



Shell small, broadly subelliptical, subattenuate toward the beak; the margins gradually expanding and cturving 

 from the beak to the center, where the shell has its greatest width, and thence narrowing toward the front, which is 

 broadly rounded. General surface depressed, convex, becoming more convex toward the beak. 



Surface marked by fine undulating concentric lines crossed by radiating lines that are seen only by the aid of a 

 strong magnifying glass. 



In form this species approaches LinguleUa ferruginea Salter of the Menevian formation of Wales quite closely, 

 but with only a specimen of the ventral(?) valve to compare with it, it is difficult satisfactorily to determine its 

 specific relations. 



From the Newfoundland material the following additional description is taken: 

 The dorsal valve is ovate and moderately convex as it occurs in the shale. 

 The shell appears to have been tliin, and budt up of two or more layers or lameUse. The 

 surface described for the type specimen is correct for the surface when the thin outer layer 

 is exfohated. The outer surface, as shown by a small bit of it on the type specimen, is of the 

 62667°— VOL 51, pt 1—12 32 



