Makcu 8, 1901.] 
of which Grammysia Acadica, Billings, is a well- 
known species, together with a number of 
interstratified, more or less, caleareous band- 
holding branchiopoda, gastropoda, trilobites 
and ostracods in abundance. 
3. THE MoyDART FORMATION (pronounced 
Modiart). This consists for the most part of 
heavy-bedded, light greenish gray and rusty, 
or buff-weathering, calcareous strata (in which 
the ‘Red Stratum’ of authors occurs) and 
holds a conspicuous fauna of brachiopods, tri- 
lobites, annelids, cephalopods, crinoids, ete. It 
is followed downward by 
4, THE McADAM FORMATION, which is char- 
acterized by dark gray or black fine-grained car- 
bonaceous and oft times splintery shales holding 
a lamellibranchiate fauna in the upper half of 
the shale and graptolites in the lower half. 
A number of thin lenticular sheets of impure 
light gray limestone abound in brachiopoda. 
5. THE ARISAIG FORMATION. At the base of 
the Silurian succession, along the Arisaig shore, 
there occur buff-weathering fine-grained and 
compact indurated sandstones and shales hold- 
ing corals (chiefly Streptelasma) brachiopods, 
trilobites, gastropods, etc. These are associ- 
ated with black carbonaceous and graptolitic 
shales. The term Arisaig formation is sug- 
gested and proposed for the lowest Silurian 
horizon or formation in the section as developed 
at Beech-hill Cove. The term Silwrian is here 
used in the restricted sense as equivalent to the 
Upper Silurian of Murchison. These forma- 
tions tabulated would give the following ar- 
rangement : 
System. Formation. Strata. 
Devonian. | Knoydart. | Red shales and sandstone, 
marls and gray sandy 
shales with tufaceous 
layers. 
Red shales and mudstones, 
with occasional thin 
bands of limestone. 
Greenish-gray and whitish 
colored impure lime- 
stones. 
Black carbonaceous shales 
and mudstones. 
Buff-weathering sandy 
shales and sandstones, 
caleareous layers and 
black carbonaceous 
shales. 
Silurian. Stonehouse. 
Moydart. 
McAdam. 
Arisaig. 
SCIENCE. 
395 
The amount of unconformity, if any, be- 
tween the Stonehouse and Knoydart forma- 
tions, z. e., between the Devonian (‘Old Red 
Sandstone’) and the Silurian is a point of con- 
siderable importance and interest which will 
receive careful attention. H. M. Amt. 
INFLUENCE OF LIGHT ON THE LENGTH OF THE 
HYPOCOTYL IN INDIAN CORN. 
IT is well-known that in vegetating plants of 
Indian corn, wheat and other cereals, the first 
node of the stem is found near the surface of 
the ground, regardless of the depth at which 
the seed was planted. If the seed is deeply 
planted, the hypocotyl] elongates above the seed 
proportionally lifting the node almost to the 
surface. If the seed is planted shallow, on the 
other hand, the node is found at about the 
same depth. 
That the checking of the elongation of the 
hypocotyl is due to the influence of light is 
strikingly shown by an experiment recently 
conducted in the laboratory of the Wisconsin 
Agricultural College. Kernels of Indian corn 
were planted by a number of students in galva- 
nized iron seed pans nearly filled with garden 
loam, after which the pans were kept covered 
with close-fitting tin covers until the plantlets 
began to appear when the covers were removed. 
In all plantlets which appeared above the 
soil before the cover of the seed pan was re- 
moved, the first node is above the soil, as is 
clearly shown by the fact that this node bears 
the cotyledon, while in those that have since 
appeared, the first nodeis just at the surface 
or below it. EK. S. Gorr. 
UNIVERSITY OF WISCONSIN. 
CURRENT NOTES ON PHYSIOGRAPHY. 
ALLEGANY COUNTY, MARYLAND. 
THE first volume of a new series of county 
reports just begun by the Maryland geological 
survey gives an excellent description of Alle- 
gany county, which occupies a central position 
in the three western mountainous counties. 
Among nine chapters, treating subjects that 
range from geology and soils to climate and 
forests, the physiography of the county is de- 
scribed by C. Abbe, Jr. The three cycles of 
erosion, characteristic of a great stretch of the 
