fold and along the east side of the Jackson fault are also favorable; that the best chances for accumulations of oil are probably in the sands above and below the Selma chalk, which lies from 780 to 2700 feet below the surface along the crest of the anticline; and finally that there are doubtless other areas of favorable structure in the adjoining region where oil and gas may have accumulated if they are present in commercial quantities anywhere in the region.

R. W. STONE

ORNITHOLOGY.-Washington region [April and May, 1917). HARRY C. OBERHOLSER. Bird-Lore 19: 211-212. 1917.

The months of April and May, 1917, were unusually cold at Washington, D. C., and the resultant spring migration of birds was peculiar. Many species of migrants that appeared in April were ahead of their usual schedule, but many that came in May were very much delayed. A number of birds rare in the District of Columbia, at least during spring, made their appearance, chiefly in May. Conspicuous among these were Phalacrocorax auritus auritus, Larus atricilla, Chlidonias nigra surinamensis, Hydroprogne caspia, Phloeotomus pileatus abieticola, Pisobia fuscicollis, and Protonotaria citrea. H. C. O.

ORNITHOLOGY.-Description of a new subspecies of Perisoreus obscurus. HARRY C. OBERHOLSER. Proc. Biol. Soc. Washington 30: 185-188. December 1, 1917.

A new geographic race of the Oregon jay is here described as Perisoreus obscurus rathbuni, from Clallam County, Washington. It is darker than either Perisoreus obscurus obscurus or Perisoreus obscurus griseus, and much more grayish above than the former, with a usually broader whitish nuchal collar. Its geographic distribution is apparently limited to that part of the State of Washington about Puget Sound and the Strait of Juan de Fuca. H. C. O.

ORNITHOLOGY.-A review of the subspecies of the Leach Petrel (Oceanodroma leucorhoa (Vieillot). HARRY C. OBERHOLSER. Proc. U. S. Nat. Mus. 54: 165-172. October 19, 1917. Notwithstanding the considerable attention that has been paid to the petrels of the Oceanodroma leucorhoa group, there is evidently something yet to learn concerning these birds. A study of the entire species, with extensive material, leads to the conclusion that three forms are recognizable: Oceanodroma leucorhoa leucorhoa (Vieillot),

which breeds in the North Atlantic and North Pacific Ocean; Oceanodroma leucorhoa beali Emerson, which breeds from southeastern Alaska to the coast of northern California; and Oceanodroma leucorhoa kaedingi Anthony, which occurs off the Pacific coast of Lower California, south to the Revillagigedo Islands, western Mexico. Of these three forms only the first and third are currently considered valid. Furthermore, Oceanodroma leucorhoa kaedingi has hitherto been treated as a species, whereas it is but a subspecies of Oceanodroma leucorhoa. H. C. O.

ORNITHOLOGY.-A new subspecies of Geothlypis beldingi. HARRY

C. OBERHOLSER. The Condor 19: 182-184. December 7, 1917. A very distinct subspecies of the Belding yellow-throat is here described as Geothlypis beldingi goldmani, from San Ignacio, Lower California. It differs from Geothlypis beldingi beldingi in its much duller and less yellowish upper parts, whitish instead of yellowish area on the crown behind the black mask, and more restricted yellow of lower surface. Its breeding range is confined to central Lower California, although a single specimen indicates its wintering in the Cape San Lucas region. H. C. O.

ORNITHOLOGY.-A remarkable martin roost in the city of Washington. HARRY C. OBERHOLSER. Bird-Lore 19:315–317. December 1, 1917.

Although late summer roosts of the purple martin are by no means uncommon in the eastern United States, there is apparently no record of a martin roost in the District of Columbia prior to 1917. During the latter part of the summer of this year great numbers of the purple martin (Progne subis subis) gathered nightly in the Mall, along Fourth Street, where they roosted in the trees along the street-car line. The birds were first noted here on August 5 and continued nightly to resort to this roost until September 9. The number of birds ranged from about 2500 to about 12,000, but the usual number was between 7000 and 8000. They assembled daily about 25 or 30 minutes before sunset and were all at rest in the trees by from 12 to 30 minutes after sunset. Their evolutions during this period were of much interest. During the martin occupation this roost regularly housed also between 100 and 500 European starlings (Sturnus vulgaris vulgaris), from 1000 to 4000 purple grackles (Quiscalus quiscula quiscula); also, on a few days, a number of bank swallows (Riparia riparia riparia) and roughwinged swallows (Stelgidopteryx serripennis serripennis). H. C. O.

ORNITHOLOGY.-Notes on North American birds. III. HARRY C. OBERHOLSER. The Auk 34: 465-470. October, 1917.

This paper contains technical notes on two genera and three species. The genus Bannermania Mathews and Iredale, recently proposed for the reception of Oceanodroma hornbyi (Gray), proves on examination of further material to be invalid, since the characters given in the original diagnosis are not constant. The name of the species should therefore remain Oceanodroma hornbyi.

The subgenus Cymochorea Coues, recently raised to generic rank by Mathews and Iredale, seems not to be worthy of this elevation. A careful examination of the species of Oceanodroma discloses the fact that there are no constant structural differences between them, and that consequently all must be included in the same genus. In view of this, Cymochorea Coues can be considered of nothing more than subgeneric rank.

A new subspecies of booby (Sula dactylatra californica), recently described by Dr. Walter Rothschild from San Benedicto Island, in the Revillagigedo group, western Mexico, although said to be from California, has apparently never been taken within the confines of that. State, and therefore must be excluded from the list of North American birds.

The name Fregata aquila Linnaeus, currently applied to the North American frigate bird, has been shown by Mathews to be applicable only to the bird of Ascension Island in the South Atlantic Ocean. The frigate birds of North America now prove to belong to two other species: that of the West Indies and southeastern United States being Fregata magnificens rothschildi Mathews, and the Pacific bird, Fregata minor palmerstoni (Gmelin).

The name Strix wapacuthu Gmelin, recently revived for the Arctic horned owl (the Bubo arcticus of Swainson), is now shown, as contended previously by Mr. Brewster, to be applicable only to Nyctea nyctea, and thus unavailable for the other species, which should therefore still be called Bubo virginianus subarcticus Hoy. H. C. O.

PROCEEDINGS OF THE ACADEMY AND AFFILIATED

SOCIETIES

WASHINGTON ACADEMY OF SCIENCES

The meeting of the Board of Managers on February 18, 1918, was devoted chiefly to the discussion and amendment of the report of a special committee on membership policy. The Board adopted rules for the guidance of the Committee on Membership, limiting the resident membership of the ACADEMY to 20 per cent of the active scientific population of Washington, as represented by the number of names in the "Red Book" (the biennial directory of the ACADEMY and its affiliated societies). The requirements for admission to membership, which are stated only in general terms in the By-Laws of the ACADEMY, were more exactly defined by the Board; the principal qualifications adopted is that "the nominee shall have attained recognition for original and meritorious scientific investigation."

ROBERT B. SOSMAN, Corresponding Secretary.

BIOLOGICAL SOCIETY OF WASHINGTON

The 578th regular meeting of the Society was held in the Assembly Hall of the Cosmos Club, Saturday, January 26, 1918; called to order at 8 p.m. by President ROSE; 62 persons present.

On recommendation of the Council, J. B. NORTON and S. F. BLAKE, both of the Department of Agriculture, were elected to membership. On recommendation of the Council a proposed amendment to the constitution was announced by which members of the Society might become life members upon the payment of fifty dollars in two annual installments of twenty-five dollars each.

Under the heading brief notes and exhibition of specimens the following informal communications were presented:

A. WETMORE remarked on food habits of grackle with reference to eating and cracking pin-oak acorns, the peculiar structure of the bill of the genus Quisqualus being specially adapted for this purpose. This was discussed by Messrs. PAUL BARTSCH, VERNON BAILEY, and F. V. COVILLE.

A. S. HITCHCOCK called attention to a recently issued flora of the Rocky Mountains by P. A. Rydberg, in which 6000 species of plants of that region are described.

PAUL BARTSCH referred to a recently received collection of Philippine shells from the island of Luzon, containing an unusually large number of new forms.

L. O. HOWARD referred to the utilization of acorns for the manufacture of alcohol.

W. L. MCATEE described the behavior of ducks, geese, bitterns, jacksnipe, and kingfishers in North Carolina during the recent continued cold weather; the kingfishers' activities being confined to the vicinity of spring holes.

The regular program of the evening was as follows:

EMERSON STRINGHAM: Notes on the speed of fishes, especially the alewife. Mr. Stringham said the question of the speed with which fish swim has elements which, it would seem, might make it popular, but there appear to be few recorded observations. It becomes of economic importance in connection with the effect of water power development on the fisheries.

Three preliminary points should be mentioned. In the first place some fish, besides swimming, are able to jump from the water and by this means pass over a current which it would be wholly impossible for them to swim through; we are not concerned here with that question. Secondly, it is assumed that if a fish can maintain itself against a steady current of so many miles an hour, it can swim the same number of miles an hour in still water. Thirdly the velocity of a stream is much less at the bottom or behind obstacles than at surface.

A Belgian engineer (G. Denil), while studying fishways, concluded that the salmon could swim at a speed of 3.15 meters a second for at least 14 meters. The author also refers to similar figures given by a French engineer. In a report on the obstructed condition of the Frazer River published in the Report of the British Columbia Commissioner of Fisheries for 1913, the author (G. P. Napier) expresses the opinion that the limiting velocity of a steady stream up which a sockeye salmon is apparently capable of swimming a very short distance lies between six and seven miles an hour. Mr. H. von Bayer, of the Bureau of Fisheries, published a paper on fishways in 1910, in which he said that the current velocity in fishways should not exceed 10 feet per second. It is remarkable that the three figures, which appear to be independent of each other, are almost identical. The Belgian estimate is about 6.9 miles an hour, the Canadian's is 6 to 7 miles an hour and the American's is 6.8 miles an hour.

In the spring of 1917 Mr. Stringham had an opportunity to study several fishways in Massachusetts, and to make some observations on the velocities of water up which the fish swam. These fish belonged to the species Pomolobus pseudoharendus (Wilson), one of the common alewives. The instrument used to measure the velocity of the water was a Price current meter lent by the Bureau of Standards. Measurements were made of the rate of flow at 7 points in the fishway where the current appeared to be greatest, and it was found to vary from 4 to 5 feet per second. At Middleboro the fish were unable to ascend a little sloping falls where the velocity was about 11 feet per second. Just below they were swimming through one place where the current was 5.3 feet per second. At East Warham the head of water, and therefore the velocity could be varied. The fish swam up a slope about 3