abstracts: ornithol,ogy 321 



rock that separate the basins. No intrusive rocks are known to cut 

 the coal measures. 



The coal of the Nenana field occurs in many beds of different thickness, 

 the thickest measuring perhaps 30 to 35 feet, which are distributed 

 rather uniformly through the coal measures. At least twelve coal 

 beds are of workable thickness, and six or more measure over 20 feet. 

 The analyses show that the coal is a lignite of good grade, of about the 

 same quality as that of Cook Inlet. R. W. StonE. 



ORNITHOLOGY. — Description of a new subspecies of the little yellow 

 bittern from the Philippine Islands. Alexander Wetmore. 

 Proc. Biol. Soc. Wash. 31: 83-84. June 29, 19 18. 



The form of Ixobrychus sinensis occurring on the Philippine Islands 

 proves to be different from all the other races of this species, and, 

 as it has no distinctive name, is to be known as Ixobrychus sinensis 

 astrologus Wetmore. It is apparently most closely allied to Ixo- 

 brychus sinensis bryani (Scale) , from the island of Guam in the Marianne 

 group, from which it differs chiefly in its smaller size, darker upper 

 parts, and paler neck. Its type is from Paete, Laguna, Luzon Island, 

 Philippine Islands, and its range extends from the island of Luzon to 

 Panay Island in the Philippine Archipelago. Harry C. Oberholser. 



ORNITHOLOGY. — The migration of North American birds. VI. 

 Horned larks. Harry C. Oberholser. Bird Lore 20: 345-349 

 (map). 19 18. 



The geographic distribution of the American horned larks extends 

 from the Arctic Ocean to Bogotd, Colombia. Twenty-three sub- 

 species are now distinguishable, most of which are resident. Five 

 subspecies not currently recognized are here revived and their geo- 

 graphic distribution delineated. These forms are Otocoris alpestris 

 enthymia, Otocoris alpestris aphrasta, Otocoris alpestris leucansiptila, 

 Octocoris alpestris, ammophila", and Otocoris alpestris enertera. The map 

 shows the distribution of all the American forms, and tables indicate 

 the migration movements of the four forms that are most migratory. 



H. C. O. 



ORNITHOLOGY.— BiVds of Glacier National Park. Florence Mer- 

 RiAM Bailey. General information regarding Glacier National 

 Park, season of 1918. 52-64. 1918. 

 This list of 184 species and subspecies is reasonably complete for 



