NATURAL SCIENCES OP PHILADELPHIA. 423 



Length about 2-75 (100) ; width -78 (28) ; thickness -25 (9) ; projection of 

 anterior extremity beyond, beaks *28 (11) ; posterior angle formed with hinge 

 line by anterior truncation 140 ; anterior angle formed by posterior trunca- 

 tion 128. 



Locality. Union, Branch county, in blue argillaceous shales of the Huron 

 group the "Kidney Iron formation" of Houghton. 



But few specimens of this interesting species have been seen, and the best 

 of these is defective at the posterior extremity ; and I have determined the 

 total length only from a restoration founded on the incremental lines. 



The three foregoing species of Solen nearly double the number previously 

 known from the Palaeozoic rocks. Messrs. Sandberger have described S. cos- 

 tatus from the Aviculaschiefer of the Spiriferensandstein group in Nassau, 

 which is supposed by them to occupy the horizon of the Marcellus Shale and 

 Hamilton group. S. pelagicus, Goldf., and S. Lustheidi, d'Arch. and Vera., 

 come also from the Devonian, but they are both doubtful species. The first is 

 referred by d'Orbigny to Cypricardia ; the latter, judging from specimens in 

 Dr. Rominger's collection from the Eifel, has the valves scarcely gaping ante- 

 riorly, and presents much the appearance of a Solemya, (see especially So- 

 lemya primceva, Phil. McCoy, Brit. Pal. Foss. pi. 3F., fig. 3). Lastly, de Kon- 

 inck has noticed a very imperfect solitary specimen, S. siliquoides, from the 

 subcarboniferous limestone of Vise, in Belgium. 



Pugiunculus, Barrande. 



Pugidncclus (?) aculeatus, Hall, (13th Rep. N. Y. Reg., p. 107). Shell 

 small, elongate, tapering, with an obtusely triangular section. Slant height 

 slightly curved on all the sides and angles ; sides also more convex in the 

 transverse direction. The two equal sides making with each other an angle 

 of 102, and with the broader side angles of 39. Specimen a cast without 

 any external markings. 



Length -43 (100) ; breadth of sides at aperture -19 (44), -12 (28), -12 (28). 



Locality. S. E. .V S. W. Sec. 23., Adams, Hillsdale county. 



This form lacks the evidence of striation attributed to Pugiunculus, Bar- 

 rande ( Theca of English authors) and presents still less agreement with any 

 other known genus. The original specimens were described from Rockford, 

 Indiana. 



Pleukotomaria, Defrance. 



Pseukotomaria vadosa, Hall, 10th Rep. N. Y. Reg., p. 108). Shell glo- 

 bosely conical, with a width equal to its height ; whorls about three, rounded 

 on the exterior, somewhat flattened where they come in contact, marked along 

 the middle by a moderately raised carina, on each side of which is a feeble but 

 distinct revolving line, and beyond this another still feebler, and sometimes a 

 third ; body whorl occupying about three-fourths of the altitude of the shell, 

 regularly curved on the base, and limited by a neatly rounded umbilicus 

 open to the apex of the shell. Aperture subcircular, but slightly modified by 

 the body whorl ; apex quite obtuse ; angle of sides 65 ; sutural angle about 

 90 on the last whorl. Cast shows the revolving lines on the last whorl, but 

 not on the preceding ones. 



Height of shell -44 (100) ; width -48 (109) ; height of body whorl -36 (82) ; 

 diameter of umbilicus (in a cast) -08. 



Locality. In a loose fragment from the western part of the State, consisting 

 of an agglomerated, silicious, sintery and somewhat ferruginous mass of fos- 

 sils, physically resembling some states of the Marshall sandstone. Described 

 here in consequence of its supposed identity with a fossil from beds which 

 appear to be the equivalent of the Marshall sandstone, at Rockford, Ind. 



Pleueotomakia Whitei, n. sp. Shell with a trochoid spire, straight colu- 

 mellar lip, and prominent carinate whorls. Number of whorls three and a 

 half, rapidly enlarging, raised in the middle of the dorsum in a prominent 



1862.] 



