110 The American Oeoloyi St. Feb. 1990. 
peculiar aqueous fauna at its base and almost as abrupt an extinciont 
of it at the top. 
Part II notes the occurrence of equivalents of the Chico-Tejon series 
in Oregon and Washington. These represent both the lower or Chico 
portion of the series and the upper or T^jon portion. Only the former, 
however, is identified in southern Oregon and northern California. 
Part III discusses the fauna of the Vancouver group, describing 
three new species. This formation is shown to be paheontologically 
equivalent, at least in large part, with the Chico strata. 
A small, unique fauna, collected by professor Newberry from the 
coal-bearing formation of the Puget Sound basin, is reported in Part 
IV, indicating deposition in a very large estuary, which was probably 
contemporaneous with the Laramie sea. 
The closing article, Part v, notices a small collection of Mesozoic 
fossils from Alaska, all of which are regarded ag new, and as probably 
belonging to strata somewhat older than the Aucella-bearing strata of 
Alaska. 
Subaerial decay of rocks and the origin of the red color of certain forma- 
tions. By Israel Cook Russell, pp. 65 ; plates 5. (Bulletin of the 
U. S. Geol. Survey, No. 52, 1889). In the study of the origin of the 
prevailingly red color of the Mesozoic sandstones and shales of our 
Atlantic border on the bay of Fundy and from the Connecticut valley 
to South Carolina, named the Newark system,^ Mr. Russell has 
examined the areas of deeply decayed rocks, covered with red soils, 
in the southern states, and compares them with similar rock decompo- 
sition and residual soils of other parts of the world. 
The mica schists and allied rocks in Pennsylvania and Maryland are 
decayed to the depth of only a few feet, but are frequently disintre- 
grated, that they may be removed with a pick and shovel, to fifteen or 
thirty feet, and occassionally fifty feet, below the surface. Nearly the 
entire area underlaid by crystalline rocks in Virginia and the Caro- 
linas east of the Blue Ridge has a soil of red clay, which is a residual 
deposit produced by the subaerial alteration of the rocks on which it 
rests. This alteration generally reaches more than a hundred feet, 
below the surface, but, owing to lack of exposures, its full extent is 
seldom seen. 
On washing the residual deposits so as to collect separately their 
grains of quartz and feldspar, scales of mica, and particles of other 
minerals, each of these sand grains, especially where the decomposi- 
tion is well advanced, has been found to be coated with a thin shell 
having a brownish or red color. Prolonged washing fails to remove 
this coating, a fact which is well illustrated by the red sands now be- 
ing deposited by the streams of Virginia and the Carolinas in the re- 
gions underlaid by crystalline rocks. Chemical analyses show that 
the incrustation is rich in both ferric oxide and alumina, being a 
ferruginous clay formed around the individual grains during the dis- 
i ntegration and decomposition of the parent rocks. 
iSee this journal, vol. in, pp. 178-182, March, 1889, 
