and sometimes a few finer intermediate lines. A few individuals show five lines on the spire, while others have only three or two. Smooth forms like that represented by Fig. 10 usually show incipient spiral lines on the last whorl.

Height of an average specimen, about 17 mm.; greatest breadth, 8 mm.; height of aperture, 7 mm.; breadth of aperture, 5 mm.

The most striking feature of the species is the variability of its sculpture, though in this respect is comparable with such living species as G. virginica Gmelin. Of about 200 specimens in the collection nearly half either lack spiral sculpture or have it very faintly developed.

The generic reference of Goniobasis is not entirely satisfactory, as the aperture differs in some respects from typical living species of the genus. It slightly suggests Lioplacodes veternus Meek from the supposed Jurassic at the head of Wind River, but it is specifically very distinct and I think not referable to the same genus. In sculpture it resembles G. tenuicarinata M. and H. from the Laramie more closely than any other fossil form.

Locality.-Wettacombe's ranch near Musselshell River, in the vicinity of Harlowton, Montana.

Horizon.-Upper part of Lower Cretaceous or base of Upper

Cretaceous.

GONIOBASIS? SILBERLINGI n. sp. Pl. IV, Fig. 6.

A single fragmentary specimen associated with the preceding seems to be worthy of description, although the generic reference is very doubtful. It is the basal portion of a shell consisting of nearly two whorls and may be described as follows:

Shell of moderate size, rather stout; whorls very convex; aperture broadly ovate; inner lip thin, slightly reflexed below over a distinct umbilical pit; surface of the spire with four strong spiral ridges or carinæ, which are unequally spaced, the space between the uppermost one and the suture and also between it and its neighbor being broader than the other smooth bands.

The fragment measures 13 mm. in height and 13 mm. in greatest breadth; height of aperture, partly estimated, 9 mm.; breadth of same, 6 mm.

The base of the aperture is broken, and it is possible that the large size of the umbilical pit is due to abnormal individual development. If this is a normal example of the species, it can hardly

be placed in the same genus with G.? ortmanni. In sculpture it suggests the carinated forms that White has very doubtfully referred to Lioplax endlichi from the Bear River formation.

Locality-Wettacombe's ranch, near Musselshell River, in the vicinity of Harlowton, Montana.

Horizon.-Upper part of Lower Cretaceous or base of Upper

Fig. 1. Right valve of type.

Fig. 2. Right valve of compressed form, probably male.

Unio douglassi Stanton.

Fig. 3. Left valve of a small specimen.

Fig. 4. Dorsal view of an average-sized specimen.

Viviparus montanaensis Stanton.

Fig. 5. Aperture view of the type, enlarged.

Goniobasis? silberlingi Stanton.

Fig. 6. Aperture view of the type, enlarged.

Goniobasis? ortmanni Stanton.

Fig. 7. Aperture view of fragmentary specimen with strong sculpture, enlarged. Outer lip restored from another specimen.

Fig. 8. Dorsal view of a similar specimen, enlarged.

Fig. 9. A specimen with only two spiral lines on the spire, enlarged.
Fig. 10. Aperture view of a specimen without spiral sculpture except on
back of last whorl, enlarged.

Campeloma harlowtonensis Stanton.

Fig. 11. Aperture view of the type.

Fig. 12. Similar view of a broader, more umbilicated specimen.

REACTION AS AN EFFICIENT AGENT IN PROCURING DEEPER NAVIGABLE CHANNELS IN THE IMPROVEMENT OF RIVERS AND HARBORS.

BY LEWIS M. HAUPT, A.M., C.E.

(Read April 2, 1903.)

Consumption, production and distribution are the three main elements of trade. Without great facilities for distribution it is not possible to maintain a nice adjustment between supply and demand. One section of the earth may be starving, while another may be burning its excess of food for lack of cheap transportation. PROC. AMER. PHILOS. SOC. XLII. 173. N. PRINTED AUG. 5, 1903.

The question, therefore, has its humane as well as its financial and scientific aspects. It is the aim of the engineer and the capitalist to reduce the cost of transportation to a minimum for the general welfare of mankind.

The great improvements which have been effected in the railways of the world have resulted in a rapid reduction in the average rates of freight, which are still falling. Roadmakers have caught the infection and are mending their ways as rapidly as the means become available. Sailing vessels are transformed into the schooner type of greater dimensions and are designed to be handled by smaller crews, so that it may be said they represent the cheapest class of carriers. The steamer also is being greatly enlarged in its capacity with the same end in view, but it has not and cannot reach the limit of its economic possibilities because of the absence of adequate channels at its terminals.

These great evolutions in transportation have been made possible in the United States by the concentration of mind, money and materials, working in harmony and resulting in a system of overland movements which is without a rival. It is the outgrowth of private capital, employed to develop limited areas, but gradually consolidated into trunk lines, and which finally, assisted by the National Government, united the two oceans. The merging of these great interests still continues and the end is not yet. These bands of steel have enabled our excess of production to reach the seaboard and be distributed to foreign markets, and it may not be out of order to glance very briefly at the magnitude of this movement. Thanks to a beneficent Providence and the industry and intelligence of our people, our exports exceed our imports by an amount greater than that of all other nations. Their increase within a generation is startling. While the population has doubled in the past thirty years, the per capita of money has increased from $17.50 to $28.66.1 The number of artisans has increased 2.7 times, while his average earnings have risen from $387 to $500 per capita per annum. The capital employed has expanded fivefold and the value of the output more than threefold. In consequence the per capita of our exports has increased in this same period from $7.29 to $18.81, of which the largest part is food-stuffs.

and

The increase in agricultural exports was over 300 per cent., that of manufactures 750 per cent., so that this country heads the 1 O. P. Austin, Chief of the Bureau of Statistics, in The World's Work.