C. F. Harti—Tertiary Basin of the Marafton. —BH 
LAMELLIBRANCHIATA. guishes two varieties : a, distorta, 
Anodon Cuvier (fresh water). B, crassa. 
nodon Batesit Woodward. . ovata Conrad 
Anisothyris Conrad (=Pachydon Gabb) 
(bracki ater). 
A, tenuis (==Pachydon tenwis Gabb, 
is Conrad, Anisothyris . cuneata Conrad. 
Hauxwelli Woodward) ;* of this| Tellina. 
Species Mr. Woodward  distin- Tf. Amazoniensis Gabb. 
in the summer of 1871 I met Mr. J. B. Steere, a graduate of 
Michigan University, who was traveling on the Amazonas, 
making natural history collections. We spent more than a 
month together, and I took him over my old ground at Hreré 
and Monte Alegre. As he was about to visit the upper Ama- 
zonas, I gave him instructions to examine the Pebas locality, 
make a geological section, showing the character and arrange- 
ment of the beds, and collect carefully the fossils. Under date 
of Jan. 26th of this year, he has written me an account of 
his visit to the locality in question, and has sent some interest- 
ig notes which give us for the first time a clear idea of its 
geological structure, and of the conditions under which the fossils 
are found 
bo pe ba be be 
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Mr. Steere says that a short distance below Tabatinga,t 
Which, it will we remembered, is just on the boundary line 
clay, with veins of oe coal dividing them. These veins 
i 
miles above Tabatinga; but owing to the shortness of the stop 
of the steamer, he was unable to examine the locality with care. 
He describes the country below Pebas as low and less than a 
hundred feet above river level, i. e., during the n. e 
fossiliferous clay beds lie near the level of the river, but they 
are covered by 20-30 feet of red clay which he compares to the 
Superficial clays so common on the lower Amazonas. Pebas, as 
already stated, is situated on the left bank of the Rio Am- 
* I sympathize with the wish to show honor to so deserving a gentleman as 
Mr. Hauxwell, but the change of the specific name from tenuis, however inappro- 
Priate the term may be, to Hauawelli, is unwise and inadmissible. 
t Tabatinga is the name given to the white feldspathic clay common all over 
Brazil Toud, Tupi, taba Portuguese form, is a yellowish clay; tinga means white. 
