3i6 The American Geologist. Novombor, \wi 
missing in the sandstones of the lower Amazonas. As "every fossil 
species has its time value," the author carefully ascertains the time- 
value of each component of the faunas described by him. Among the 
five species of gastropods, referred to Platyceras, there are none which 
suggest the common or characteristic nodous or spinous forms of the 
Upper Helderberg fauna of New York; the seamless trilobed Bucan- 
iell.as, like B. reissi, as well as the representatives of the new genus 
Plectonotus, point to forms of the Spiriferen-sandstein instead of to 
American Devonian faunas, while the type of structure represented by 
Bucania freitasi is evidently repeated in Bellerophon leda of the Ham- 
ilton group, and similarly Ptomatis forbesi finds its congener in P. 
patula of the Corniferous and Hamilton faunas. 
Among the Pelecypoda, which in this fauna strangely outnumber 
the Brachiopoda, the common Actinopteria eschwegii is a new ally to 
A. boydi, so abundant in the Hamilton group of New York, and oc- 
curring in the Corniferous limestone of Ohio, the whole genus being 
eminently lower Devonian. The genus Liopteria, which is acmic in the 
middle Devonian, is represented by only one, evidently rare species, 
while the species of Modiomorpha are of types represented in the 
Schoharie grit and Corniferous limestone. The new schizodoid genus 
Toechomya shows aflinities to species of the Corniferous limestone and 
Spiriferen-sandstein, while one of the Sphenoti (Sph. groceixi) is 
compared with a Hamilton form. Shells of the structure of the Cimi- 
taria karsteni occur in the Spiriferen-sandstein, and one of the Cyp- 
ricardellas (C. hartti)has its congener in the lower Devonian of North 
America and Germany, as well as in the middle Devonian of New 
York. The Grammysias belong to divisions which have no represent- 
atives in the North American fauna earlier than the Hamilton. Nucula 
bellistriata Conr., var. parvula represents a type elsewhere of middle 
Devonian import, and the Nuculites smithi finds its nearest ally in the 
Hamilton group. Paleoneilo orbignyi belongs to a middle and upper 
Devonian type of North America. 
The brachiopods, which have been studied by Mr. Rathbun, are 
also subjected to an analysis to determine their time-values, and the 
following results are obtained: The species of Productella (M) is 
similar to P. shumardana of the Corniferous limestone at the Falls of 
the Ohio; Chonetes comstocki (E and M) can be compared with C 
complanata of the Orikany sandstein: Ch. freitasi and Ch. curuaensis 
belong to types common in the Upper Helderberg. A small brachio- 
pod from the Curua-sandstone has been identified by the author with 
the Anoplia nucleata, which is often very abundant in the Oriskany 
sandstone, but occurs also in the Upper Helderberg limestone about 
Cayuga, Ontario, where the fauna embraces many characteristic Oris- 
kany species. The species Sreptorhynchus (Orthothetes) agassizi is 
hardly distinct from O. chemungensis, especially from its earlier, more 
rigid subforms, as O. woolworthana. The numerous species of Spirifer 
occurring in the fauna do not yet allow of a precise comparison, but 
one form labelled by Rathbun as Sp. maecuruensis, bears a striking 
