NO. 1862. FOSSIL FERNS FROM THE POTOMAC GROUP— BERRY. 325 



that the modern genus Thyrsopteris was a promment Jurassic and 

 older Cretaceous type, there bemg many parallel cases, as, for example, 

 that of the gymnospermous genus Ginkgo. Some of the evidence is 

 at least sufficient to prove that forms so named are referable to the 

 family Cyatheacefe, so that in considering the Potomac forms we 

 have to decide whether the fact that the Jurassic forms like Thyr- 

 sopteris maakiana and Thyrsopteris murrayana of Heer are members 

 of the Cyatheaceae, shall be given greater or less weight than the fact 

 that the same type of sterile frond very abundant in the Lower Cre- 

 taceous, from England to Japan, should have fertile pinnules like those 

 of the genus OnycJiium of the Polypodiace?e. It is true that only 

 sterile pinnules are knovvTi from the Potomac deposits, but the fertile 

 parts have been found associated and in organic connection with 

 these identical sterile pinnules in nearly homotaxial beds in California, 

 Japan, England, Belgium (?), Bohemia, and Portugal. The writer 

 prefers to believe that the latter evidence is entitled to the greater 

 weight. The modern genus Onychium has several widel}" distributed, 

 chiefly tropical, species of Japan, China, India, Persia, Abyssinia, and 

 the East and West Indies. In this connection attention should be 

 called to the fertile specimens described by Professor Fontaine, from 

 Fredericksburg, as Aspleniopteris, since the latter, which is referred 

 to the Aspleniese, is ver}^ similar to the fertile pinnae of a specimen of 

 OnycMopsis goepperti from Japan, kindly communicated by Professor 

 Yokoyama. 



ONYCHIOPSIS GOEPPERTI (Schenk) Berry. 



Sphenopteris goepperti Schenk (part), Palaeont., vol. 19, 1871, p. 209 (7), pi. 30 



(4) figs. 2, 2a (not figs. 3-5 or pi. 35 (9) fig. 2).— Saporta, Flora Foss. Portugal, 



1894, pp. 71, 123, 159, pi. 18, fig. 6; pi. 33, fig. 8; pi. 29, fig. 6. 

 Thyrsopteris elongata Geyler, Palaeont., vol. 24, 1877, p. 221. — Schenk in 



Richthofen's China, vol. 4, 1883, p. 263, pi. 54, fig. 1. 

 Dicksonia elongata Yokoyama, Bull. Geol. Soc. Japan, vol. 1, No. 1, 1886, p. 5. 

 Onychiosis elongata Yokoyama, Joum. Coll. Sci. Japan, vol. 3, 1890, p. 27, pi. 2, 



figs. 1-3; pi. 3, fig. 6d; pi. 12, figs. 9, 10.— (?) Seward, Wealden Flora, pt. 1, 



1894, p. 55, pi. 2, fig. 2. 

 Thyrsopteris rarinervis Fontaine, Monogr. U. S. Geol. Surv., vol. 15, 1890, p. 123, 



pi. 26, figs. 6, 7; pi. 43, figs. 4-6; pi. 44, figs. 1, 2, 5; pi. 49, fig. 2; pi. 169, 



figs. 6, 7. — Fontaine, in Ward, Monogr. U. S. Geol. Sm-v., vol. 48, 1906, pp. 



225, 484, 491, 514, 517, 518, 521, 528, 548, pi. 65, figs. 2-A; pi. 113, figs. 2, 3. 

 Thyrsopteris alata Fontaine, Monogr. U. S. Geol. Surv., vol. 15, 1890, p. 124, 



pi. 36, fig. 3. 

 Thyrsopteris meehiana angustiloba Fontaine, Monogr. U. S. Geol. Surv., vol. 15, 



1890, p. 126, pi. 38, figs. 5-7, 9; pi. 43, fig. 8; pi. 44, fig. 3; pi. 47, fig. 4; pi. 48, 



fig. 1; pi. 54, figs. 2, 11; pi. 55, fig. 1; pi. 56, figs. 1-3. — Fontaine, in Ward, 



Monogr. U. S. Geol. Surv., vol. 48, 1906, p. 557. 

 Thyrsopteris angustiloba Fontaine, Monogr. U. S. Geol. Sm-v., vol. 15, 1890, p. 134, 



pi. 48, figs. 3-5; pi. 55, fig. 3. 

 Thyrsopteris densifolia Fontaine, Monogr. U. S. Geol. Surv., vol. 15, 1890, p. 129, 



pi. 39, fig. 3; pi. 40, figs. 2-5; pi. 51, fig. 5. — Fontaine, in Ward, Monogr. 



U. S. Geol. Surv., vol. 48, 1906, pp. 484, 511, 517. 



