PXPRIL, “15, TONS || 
NATURE 
Lay, 

RECENT WORK OF THE UNITED STATES 
GEOLOGICAL SURVEY. 
N No. 82 of the handsome series of Professional 
_ Papers published by the United States Geological 
Survey, Myron L. Fuller describes ‘‘ The Geology of 
Long Island, New York.’’ ‘This suburban island, 
from the lively beach of Coney Island on the west to 
the old-time refinements of Easthampton, protects the 
Connecticut coast for more than a hundred miles. 
Its core consists of sandy strata, which are now 
recognised as Cretaceous; these appear at the base of 
the bluffs of the north coast and in wells in the 
interior. The early events of the Ice age piled the 
Manhasset Formation across them, and on the some- 
what irregular plateau. thus built up two great 
moraines were deposited as records of the Wisconsin 
epoch of ice-advance. One of these appears con- 
spicuously along the axis of the island, while the 
younger moraine lies near to the north coast. The 
sandy plains formed by the outwashed material from 
these ridges cover a large part of the country. The 
present memoir, with its two large folding maps, may 
not appeal to the motorists who de- 
nude che roads on Sundays; but it 
will be prized on the shelves of those 
cultured citizens who have built their 
summer homes among the gracious 
woods and inlets of the sound. 
It is a long stretch from the New 
York shores to the shifting mouths 
of the Mississippi. E. W. Shaw, in 
No. 85-B, deals with the mud lumps 
that attracted Lyell as examples of 
the seaward growth of land, and 
concludes that they arise from the 
creep of semi-fluid. clay from be- 
neath the land and the shallows, 
under the pressure of new alluvium 
deposited by flooding. Where cur- 
rents sift the delta-material, leaving 
sandy banks behind, the resistance 
to outward flow is sufficient to 
cause the moving clay to rise up 
to the surface.- Some of the lumps 
stand 8 ft. above the water. 
Unless they subside, they are 
worn away: by the sea in a 
few years. The reader of this 
paper must remember that a “‘ pass”’ 
in the delta is not a _ passage- 
way, but a delta-finger dividing one bay from 
another. , 
Oklahoma, the paradise of protected Indians, is 
being explored for oil-pools, and the illustrations in 
Bulletin 547 introduce us to the broad alluvium-filled 
valleys of the country, in which the rivers may run 
almost dry, while sand-dunes (p. 31) may gather near 
their banks. The conditions remind us of those of 
Permian times in England. Another interesting view 
of river-action in easily denuded strata is given in 
Bulletin 575, where the Grand River, a tributary of 
the Missouri in South Dakota, is seen meandering 
on a great plain of level Pierre Shale, leaving outliers 
of the more resisting Foxford Sandstone, the highest 
marine Cretaceous deposit, standing out above it. To 
the west, in Wyoming, the Cretaceous beds, though 
still frequently. horizontal, are associated with moun- | 
tainous. outcrops of contorted Carboniferous rocks, 
and the rainfall allows of a thick growth of trees 
across them (Bull. 543, ‘‘ Lincoln County, Wyoming,” 
by A. R. Schultz). In Professional Paper 78, W. H. 
Emmons and F. C. Calkins guide us through a high 
NO. 2370, VOL. 95| 

and ice-carved region around Philipsburg in western 
Montana, which was lifted from the sea with the 
central Rocky Mountains in earliest Eocene times. . 
Pre-Cambrian rocks here come to Jight, and it is 
interesting to note that features of stoping and inti- 
mate penetration, resembling those so well seen in 
Finland, have arisen in them by the intrusion of 
Cainozoic granodiorite during the general uplift 
(Fig. 1). A careful description is given of the pro- 
ducts of contact-metamorphism and of exhalation from 
the igneous invaders. The district includes ores of 
gold and silver, imported by these early Cainozoic 
intrusive bodies (p. 186). The first mining operations 
were undertaken twenty-five years before the arrival 
of the railway, and exploitation has now so far worked 
away the ores that the small town of Philipsburg 
may look forward to relying on its agricultural indus- 
tries. The usual beautifully printed maps accompany 
this memoir. 
Early Eocene granite appears on the west flank of 
the mountains in Idaho (Bulletin 528, ‘‘Geology and 
Ore Deposits of Lemhi County,” by J. B. Umpleby), 
and it suffered from erosion in Middle Eocene times 

Fic. 1.—Stoping and absorption-features at contact of Cainozoic granodiorite and Algonkian sediments, 
Storm Lake, Montana. 
(p. 43). Gold-bearing veins are associated with the 
rhyolitic lavas that broke out in the area in the 
Miocene, and possibly the Pliocene period, and this 
bulletin is largely concerned with mining. The main 
routes for traffic are eastward; the differences of 
elevation cause a great variety of climatic conditions 
in Lemhi County, but the photographs around Salmon 
City have a distinctly pleasing air. The same author 
describes a somewhat similar region in Bulletin 539 
(“Some Ore Deposits in North-Western Custer 
County, Idaho”’), where the open season lasts from 
the beginning of May to the end of October, and 
where tetrahedrite and galena are mined at 8000 ft. and 
upwards above the sea. A remarkable erosion-surface, 
developed near base-level in Eocene times, has left 
traces that are now elevated to 9600 ft., with valley- 
floors 5000 ft. below them. The mines on Poverty 
Flat thus stand at 9500 ft., on the margin of a partly 
wooded plateau covering twenty-five square miles, 
which has been worn as a peneplane across steeply 
tilted Palaeozoic rocks. As a result of elevation, 
valleys were developed in the Miocene’ lacustrine 
