690 PROCEEDINGS OF THE NATIONAL MUSEUM. voL.xxin 



sufficient clearness to permit me to describe them. A tubercle on 

 each side of the median line, just in advance of the area, indicates the 

 main vascular sinus, and a depression marks the position of the ante- 

 rior portion of the visceral cavity. 



OhscTratums. — This is probably the oldest species of the subgenus 

 Lingulella. It is associated with Acrothele ecclata, Ole7ieUusam2^ho!d6S, 

 and other characteristic species of the Lower Camlirian fauna. In its 

 elongate dorsal valve it recalls Oholus rhea of the Middle Cam])rian. 

 It differs from that species in the character of the shell and the outline 

 of the valve. 



The specific name is given in honor of IVIr. Charles Schuchert. Avho 

 collected the only specimen of the species known to me. 



Formation and locality. — Lower Cambrian conglomerate and l>ed- 

 ded limestone, Troy. New York. 



OBOLUS (LINGULELLA) SIEMIRADZKII, new species. 



Linguhi sji. ef. e.nmguif! Eichwald, Sieiuiradzki, Jahrb. K. K. (Teol. Reichsanst., 



1886rXXXVI, p. 672. 

 LinguJa cf. exioigiils Eichwald, Gurich, Xeiies Jahrb. ]Min. Geol. Pal. 1892, I, 



p. 69; Verhandl. (Zapiski) Euss. Kais. I\Iin. Gesell., St. Petersburg, 2d ser. 



1896, XXXII, pp. 17, 214. 



Attention was called to this species by Dr. Jos. Siemiradzki in 1886 

 in connection with his study of the Paleozoic rocks of the ^Middle 

 Mountains of Poland. He speaks of it as Lingula sp. in the BLick 

 conglomerate, comparing it with L. ex\>n(juh Eichwald.^ In the asso- 

 ciated gray sandstone he found an Olxdus ''identicar' with (). xUnricus 

 Eich. 



Dr. G. Gurich wrote on the Paleozoic of the Middle ]Mountains 

 (Mittelgebirge) in 1896, and. in a discussion of the Cambrian of San- 

 domir, mentions Siemiradzki's discovery of fossils in the lower sand- 

 stones and shales.'^ 



Dr. Gurich added g-reatly to the fauna found by Dr. Siemiradzki. 

 He mentions Paradoxides resembling- P. te-ssina, P. lj()hc)nieu><,A(jno><tus 

 fallo.i' Linnams, ^i. glhhus Linna?us, Ziostracus I in narss-oni and refers 

 the fauna to the Middle Cambrian. The ' ' Lingula " he compared with 

 Llngula crassa. Eichwald, calling- attention to the resemblance in the 

 surface characters, also to those of Lingulclhi davl.'^il Salter. 



This is a small shell Ijelong-ing to the group of species containing 

 O. (Z.) ferrug incus, 0. (Z.) dexidcrat >(■•<, etc. The outer surface is 

 marked b}^ concentric, slightly undulating and imln-icating strisi? of 

 growth, and the outer surface of the inner layers l\v fine, radiating 

 stria\ 



Through the kindness of Dr. F. Schmidt, I received a fragment of 



Mahrb. K. K. Geol. Eeichsanst, XXXVI, 1886, p. 672. 



-Xeiies Jahrl). Min. Geol. Pal., I, 1892, p. 69; Verhandl. (Zapiski) Kuss. Kais. :\Iin. 

 Gesell., St. Petersburg, 2d sen, XXXII, 1896, p. 17. 



