Revieiv of Recent Geological Literature. 317 
resemblance to the common North American AmbocoeHa umboniata. 
The two Retzias (Rhynchospiras ? according to Clarke), described by 
Hartt, are of much interest, as similar forms have not been found 
above the Lower Helderberg. The Rhynchoneila dotis from Erere 
identified by Rathbun, is supposed by Clarke to be identified with the 
Corniferous limestone form Rh. sappho. The abundant occurrence of 
Amphigenia elongata in both the Maecuru and Curua sandstones is a 
striking character of the brachiopod faunas. Also Tripidoleptus cari- 
natus and Vitulina pustulosa are abundant. 
The fauna of the sandstone of Erere reveals itself by its brachiopods 
trilobites, pelecypods, gasteropods and pteropods alike as a miniature 
of the Hamilton fauna; in fact, it is a more typical and better defined 
middle Devonian fauna than the latter, because it is equally free of 
types of earlier and of later Devonian faunas. Intercalated in the 
sandstones about Erere are layers of dark shale, which contain Orbi- 
culoidea lodensis, and Lingula spatulata, and are thus characterized 
as the equivalent of the Genesee shales. 
The sandstone of the Rio Curua, while connected with the Maecuru 
sandstone bj' its brachiopod element, differs from the latter by the 
almost entire absence of the trilobites, pelecypods and gasteropods, 
so abundant in the Maecuru sandstone. Though it, therefore, may be 
properly regarded as a member of the Maecuru group, it does not 
contain the same fauna. ^Ir. Clarke suggests, on account of the much 
rarer occurrence on the Curua of fossils also known to exist in the 
Erere fauna than on the Maecuru, that the Curua fauna is older than 
the Maecuru fauna. The Maecuru group probably embraces not only 
the Upper Helderberg fauna, btit also elements that elsewhere precede 
this, and molluscan species that are elsewhere associated with middle 
Devonian faunas, thus furnishing another interesting instance of the 
commingling of Devonian faunas which are separated in central New 
York. 
Finally is mentioned Mr. Derby's Curua group, consisting of black 
and reddish shales with no fossils but Spirophyton typum Hall and 
sporangia, which were described by Sir William Dawson as Proto- 
salvinia. and considered as the fruit of Spirophyton typum. 
A list of the fossils described from the Devonian faunas of the val- 
ley of the Amazonas with a table showing the vertical and geographical 
distribution of the same or allied specific type, increases greatly the 
usefulness of the publication. h. r. 
Analysis and Composition [0/ Roscoclite\. By W. F. Hillicbrand. 
(Am. Jour. Sci. 157, 45I-4S-!-) 
Samples of this vanadium mica from Eldorado county, California. 
were analyzed by the author with a view to reconciling the discrepan- 
cies between the ainalyses of Roscoe and Genth, and to establish a sat- 
isfactory formula. A detailed description of the methods used in the 
determination of vanadium is given. The analyses varied from those 
of Roscoe in that no manganese or calcitmi was fotind. and from those 
of Genth in having over three per cent, more ViiOs. m. l. k. 
