Rcz'iczi' of Recent Geological Literature. 47 
be traced directly to the immediately enclosing hill^. In no case have 
I ever found a scratched surface. The gravels are merely immense 
quantities of rubbish which have slid into the valleys when the moun- 
tains were of greater bight, have become covered in a comparatively 
short time with a carpet of turf and peat, due to the constant periodic 
growth and rotting of the almost tropical Siberian vegetation, and have 
thus lain there undisturbed, the gentle grades of the present streams 
not being sufficient to clear the valleys of these masses of detritus. 
Under any other than Siberian conditions, perhaps such thick beds of 
sub-angular and even angular irregularly disposed gravels might not 
be possible. A discussion of these conditions is, however, one that 
may be prolonged to a considerable length, and properly forms the sub- 
ject for separate consideration. 
Berlin. October, icoo. Chester ^^'El.Ls Pikixctox. 
REVIEW OF RECENT GEOLOGICAL 
LITERATURE. 
Ucber Auhicuiiicrclla ein netics Brachiopodengcschecitt: vox Fried- 
rich Baron Hovnixgex-Huexe (Verhandlungen der Kaiserlischen 
Russischen Mineralogischen Gesellschaft zu Petersburg. Zweite 
(Serie. Band xxxviii, No. i.) 
On the ventral valves of two species of brachiopods from the higher 
Lower Silurian (Ordovicean) of the Baltic provinces Baron Huene has 
founded the above genus with the following diagnosis : Ventral valve 
more or less convex, smooth or concentrically longitudinal, keel-like 
median fold. Beak almost entire^' atrophied. Pedicle opening unknown. 
Inside there is a large triangular platform, without median support, con- 
nected at the sides with the shell. Hinge border slightly raised; hinge 
teeth rudimentary or lacking. Dorsal valve unknown, apparently flat 
or concave. Two species are known. The most remarkable peculiarit}' 
of this genus is the large even platform, with a concave space under- 
neath. In this connection comparisons are made with Merista (?) 
cyinbula Day, and for the medium plate or septum with Orthisina CCIit- 
ambonites) diversa Shaler. Comparisons are also made with Camarella 
and Syntrophia. 
Five figures in the text and a plate of figures of the two species of 
the new genus arc given. c. F. m. 
Siippleiiiciit zii der bcsclircibung der Silurisclicn Craniadcn der Ost- 
scclandcr. By the same author and published with the former 
article. 
This is a continuation of Baron Huene's work on the Craniadae 
which appeared about a year ago and was reviewed in this journal. In 
this are described a number of new species, Pholadops, one species, 
Philhedra. five species, (and notes on two others already described), 
