NO. 1313. LOWER DEVONIC OF MARYLAND— SCHUCHERT. 415 



Mississippian Middle Devonic transgression did not attain its g-reatest 

 extent until Marcellus time, when it crossed the Ilelderhergian barrier 

 and completely invaded the Cumberland Basin as far (Mist as the Ap])a- 

 lachian Valley fold. Then the Atlantic fauna again spread into the 

 Marcellus sea of the Mississippian province. 



Jim'intiu TiiMcarora^ and-Nlagaran deposits of Cumherland Basin.— 

 In the present paper the lower members of the Ontaric will not 1)6 

 further described than to mention that the formations beneath the 

 Salina have a united thickness of 1,934 feet. More detail is given in 

 the composite section (pp. 423-4). The fauna from these formations 

 is at present a small one, and outside of Arthi'o2>Jiycus /ia7'Jani, Atryjm 

 /Ytic(/Iari.% and L<q>txna rhomhoidalis,2i\\ the species appear to be new. 

 While these formations have the position of the New York Medina, 

 Clinton, Rochester, Lockport, and Guelph, they are not all to be 

 called by these names, because, in the absence of characteristic species, 

 the faunas indicate that the Maryland Niagaran deposits belong to 

 another sea province. The conspicuous life element of these sedi- 

 ments is represented by a few species of Ostracoda, which are at 

 times so wonderfully prolitic as to make up. in large part, limestone 

 bands 2 to 4 inches thick. These foi-ms appear in the so-called Clin- 

 ton, attain greater development in the thin limestone bands of the fol- 

 lowing formation, and in the Salina are the essential fossils, where the 

 small Ostracoda are joined by large Leper ditia. The other fossils of 

 the lower formations are a few species of brachiopods of the genera 

 BJnjnehnnella and Bhyneho.pira; sometimes quite prolific, and of the 

 trilol)ites Odymene. Dahnanites, and Ilomalonotas. This faunal 

 development is wholly unlike that of the Niagaran of the interior 

 United States, and is known to be restricted to the Appalachian 

 region from southern Virginia north into New York. For this 

 area note the absence of the following fossils characteristic of the 

 New York Niagaran: Spirifer radiatus^ 8. niagarenMs, S. crispus, S. 

 sidcatus, Pentamenix oUongus, Caryocidnus, Eucalyptocrinus, etc. 

 These facts show that the Maryland faunas were probal)ly derived 

 from the east or the Atlantic during Siluric time, and that this sea 

 then had no communication with the one farther west, which Walcott 

 has called the Mississippian sea." 



Sallixi formaf ion. —Ton miles southwest of Cumberland, along the 

 line of the Baltimore and Ohio Railroad, and a little west of the sta- 

 tion of Pinto, Maryland, there is a splendid section of Salina rocks. 

 Every foot of the 1,125 feet in the vertical beds of this formation, 

 which is described in detail in the composite section, can here be 

 studied. The Niagaran deposits are seen to ptiss without apparent 

 break into the Salina, but no part of its fauna is found higher up, 



«Proc. Amer. A^=soc. Adv. Sci., XLII, June, 1894, pp. 129-169. 



