54 0. F. Hartt—Tertiary Basin of the Marafion. 
pronounced drift ;” while in his ‘“ Andes and Amazon” he 
simply says that the fossils occurred in a fossiliferous bed inter- 
ealated between the variegated claysso peculiar tothe Amazon,’* 
and that “‘interstratified with the clay deposits are seams of a 
highly bituminous lignite.¢” Prof: Orton therefore leaves it to 
be inferred that the Pebas beds are traceable down the whole 
length of the yer i Mr. Henry Woodward, in the paper 
just quoted in a foot note, says that the Pebas clays are ‘ evl- 
dently Bed IT. of Prof. Agassiz’ s section.{” Orton sub- 
mitted his fossils to Mr. Gabb, who described ay renin them§ 
under the names of Neritina pupa, Turbonilla minuscula, Mesalia 
Ortoni, Tellina Amazoniensis, Pachydon obhqua and P. tenua. 
In Mr. Gabb’s opinion these remains indicated a fauna of Ter- 
tiary age. On the strength of this opinion Prof. Orton ven- 
tured to attack Prof. Agassiz’s theory of the glacial origin of 
the valley of the Amazonas, laying stress on the fact that the 
shells occur well preserved, in _ place, and “ showing” no indi- 
cation of a “‘ grinding glacier.” 
Under the instructions of Prof. Orton, Mr. Hauxwell, an 
intelligent naturalist, resident some 30 years on the Amazonas, 
made larger and more complete collections of these shells and 
found the fossiliferous beds elsewhere on the Marafion, especially 
at Cochaquinas on the southern side of the river. These col- 
lections were placed in the hands of Mr. Conrad, who described 
them, distinguishing ten species of gasteropods and six of lamel- 
libranchs, referring all the latter to the genus Pachydon (Aniso- 
thyris Conrad). More recently Mr. Hauxwell sent large collec- 
tions to England. Those in the ete as of Mr. Janson of 
London were examined by Mr. Henry Woodward of the Brit- 
ish Museum, and form the subject of the paper already twice 
referred to. Mr. Woodward makes several changes of nomen- 
clature, and describes two new species. The list of the Pebas 
fossils now stands as follows: 
GASTEROPODA. Hemisinus Swainson (freshwater !) 
Tscea —— (freshwater ?) bag cise Conrad. 
coher Conrad=Mesalia Ortoni| Py™s Conta 
ph mrad. 
Neritina Lamarck (fresh and brackish 
os mrad, 
Li d (freshwater ? he gla . 
ri Cora re nag ) N. pupa Gabb (=N. Ortoni Con- 
Ebora pL pnvereohag or marine ?) pares Sopot (land). 
‘a Conrad. 
Nesis subsgen of sean ~ Purbnila isso. 
— T. minuscula Gabb. 
Odostomia ? Woodward (brackish water). 
* Andes an + Op. cf 
¢ Bull. de Ta Soe. oe Geel. de France 24 Série, T. xxv, p. 685. at, ‘Geol. and Phys. 
Geog. of Brazil, p 
§ Amer. Jour. Sai vol, iv, 
toe 
