Rcviciv of Recent Geological Literature. uj 
geological sketch map. This region is for the most part occupied by a 
series of Eocene sediments to which he applies the name Stepovak 
series, and divides them into upper and lower. They have been c<)n- 
siderably folded and faulted, and intruded by a laccolitic rock, a dior- 
yte porphyrytc that sends oflf numerous radial dikes into the adjoin- 
ing sediments. The lower Stepovak beds are coarse breccias and ag- 
glomerates and fine tuffs cemented by secondary silica and by other 
alteration products, the whole plainly of pyroclastic origin, and but 
slightly fossiliferous. They are hence probably of local and perhaps 
quite restricted distribution and will be difficult to co-ordinate with 
any other igneous rock mass in Alaska. The upper beds are evidently 
of marine deposition, consisting of soft shales, sandstones and grits, 
with some thin beds of limestone and now and then a chert band. They 
are the principal rocks of the region, forming the coast line, having a 
thickness apparently of more than a thousand feet. According to Dr. 
Dall the fossils found in the Stepovak series denote the Claiborne 
(Middle Eocene) age. 
Dr. Palache describes and figures a laccoli'^h of intrusive rock in the 
Stepovak series, exposed near the summit of Chicagof peak. The in- 
trusive rock is augite-dioryte-porphyryte, dark colored, gray to green- 
ish-gray and fine-grained with porphyritic crystals of hornblende and 
labradorite, more rarely of augite. The author speaks of hornblende 
surrounding pyroxene cores, but "clearly original." From this lac- 
colith numerous radiating dikes pierce the sedimentary rocks, the pre- 
vailing type being an alkali-syenyte-porphyry, the porphyritic element 
being black hornblende, while in the groundmass are crystals of albite, 
and but rarely an insignificant amount of quartz. Ofher dikes are pe- 
trographically named latyte, hornblende-dacyte, dioryte-aplyte, dioryte- 
porphyryte, olivine diabase and diabase porphyryte, without chemical 
analyses. 
In the section on minerals Dr. Palache enumerates all minerals seen 
by the partj', not including the rock-forming minerals. He modestly 
states that this catalogue is not extensive, but it contains S3 names. 
The invertebrate fossils of the Neozoic are described by Dr. W. H. 
Dall, the oldest being those of Stepovak bay. The next higher are 
"logically" the Kenai series on the peninsula separating Port Moller 
from Herendeen bay immediately to the westward. These are coal- 
bearing, and are overlain by a thinner series of Miocene age which is 
also much broken by volcanic dikes and intrusions of lava, found in 
numerous localities along the north shore of Popof island. An im- 
portant stratigraphic result of the expedition therefore is the addition 
of a fully established lower series to the Eocene of Alaska. Of the 
Stepovak fauna there are 34 species, of which 32 species are from the 
"upper beds," and two, belonging to Modiolus and Cassis, but un- 
identifiable as a species, are from the lower, or volcanic beds, of the 
whole number eleven being described as new. 
To the Kenai. or Astoria, ?erie? of the Miocene Dr. Dall refers the 
fossils from the Shumagin island?, immediately south of Stepovak bay. 
