432 Review of Recent Geological Literature. 
On the Fauna of the Lower Coal Memuret of Central Iowa, and Descrip- 
tions of two new Fossils from the Devonian of Iowa. By Charles R. 
Keyes. From, the "Proc. Acad. Nat. Sci.," Phil., July 31, 1888. Mr. 
Keyes enumerates 55 species, of which three are described as new. These 
are Chattetes heois, Pleurotomaria modesta and P. humilis, illustrated by 
figures. The faunal features of the assemblage are thus summed up : (1.) 
In those groups having an optimum habitat marine, there was not only a 
fewness of species, but also an extreme paucity of individuals. (2.) Brach- 
iopods though well represented in both genera and species, were in fact 
not as proportionately abundant as might be expected when it is remem- 
bered that this type of life had now nearly reached its greatest expansion 
and culmination, and (3) the fauna was predominantly molluscan — nearly 
two-thirds of the entire number of species. 
The two new Devonian species are Conocardium altum and Cyrtoceras 
opimum — also illustrated. 
Glacier erosion in Norway and at high latitudes. By Prof. J. W. 
Spencer, Ph. D., F. G. S. (American Naturalist, March, 1888. Read before 
the Am. Asso. for Advancement of Science, 1887.) 
Any original observation upon glaciers can hardly fail to be valuable. 
Speculation so prevails, and seems so inefficient in solving the vexing 
problems of Quaternary geology, that our main hope is in learning more 
•of the resources of nature by the further investigation of glaciers and other 
ice agents now existing. 
We have in this paper that which has been appreciated even by Norway 
geologists. Prof. Gustaf Lindstrom, of the University of Sweden, says : 
" We have not for a long time had such an important contribution to our 
knowledge of glacial geology. There are really new facts put forth, of 
which we were ignorant in spite of all that has been written on glaciers in 
Norway and other lands." 
He found glaciers arching over from rock to rock when the underlying 
surface is uneven. He found that boulders when in contact with the rock 
below, as a rule become stationary, and allow the ice to flow around them, 
producing long grooves in the lower surface of the glacier. Surpassing 
similar observations by Profs. Sexe and Niles, he found this true even 
upon surfaces sloping quite abruptly down the glacial current. He found 
that the scoring of rock surfaces was a less frequent result of glaciation 
than has been supposed. In the bed of a glacier (Fondalen) which con- 
tained little sand and a few stones, the rock surface simply appeared 
weathered with scarcely a trace of scratching or polishing. He found no 
real case of glacier pushing up a moraine in good orthodox style, though 
there was a semblance of it in a few instances. 
Hfc is fully satisfied that land-ice, never attaining a velocity as he be- 
lieves over three feet a day, can never push along boulders when they rest 
squarely on the subjacent rock, much less tear away blocks from their 
beds, and therefore above the sea glaciers have no eroding power. He 
claims that great velocity in glaciers occurs only where their base is below 
the sea level, where flotation may largely explain it, and in such cases 
rocks may be held firmly as powerful instruments of erosion. 
