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BULLETIN 15 3, UNITED STATES NATIONAL MUSEUM 



Eremialector lichtensteinii abessiniciis. 



Streptopelia decipiens griseiventris. 



Streptopelia capicola hilgerti. 



Carine noctua somalieusis. 



Mirafra sharpei. 



Parisoma leucomelaena somaliensis. 



Cercomela melanura lypura. 



Apalis flavida viridiceps. 

 Eremomela griseoflava archeri. 

 Prinia somalica somalica. 

 Eurocephalus rnppelli erlangeri. 

 Lanius antiuoiii antinorii. 

 Rhodophoneus cruentns cruentus. 

 Onychognatbus blythii. 



A few comparable forms typical of the Southern Somali area are : 



Eremomela griseoflava flavicrissalis. 

 Prinia somalica erlangeri. 

 Eurocepbalus rueppelli deckeni. 

 Nilaus brubru minor. 

 Lanius dorsalis. 

 Lanius somalicus mauritii. 

 Laniarius ruficeps. 

 Pomatorhyncbus jamesi. 

 Rliodopboneus cruentus bilgerti. 

 Cosmopsaris regius. 

 Galeopsar salvadorii. 



Francolinus sepbaena jubaensis. 

 Eupodotis canicollis somaliensis. 

 Cursorius cursor littoralis. 

 Eremialector licbtensteinii byperytbrus. 

 Streptopelia decipiens elegans. 

 Streptopelia capicola somalica. 

 Streptopelia reichenowi. 

 Mirafra collaris. 

 Antbus nicbolsoni nivescens. 

 Bradornis bafirawari. 

 Erytbropygia bamertoni. 

 Apalis flavida malensis. 



3. The Abyssinian Highland Area. This comprises the largest 

 highland area in Africa, and, as far as the very meager geological 

 data indicate, the oldest mountainous area in the continent. It may 

 be described roughly as a high plateau fringed and spotted with 

 mountain ranges and broken into two parts by the faulting of the 

 Kift Valley. Because of the abruptness of the escarpment on the 

 north, west, and east, the highland region is unusually well defined 

 geographically. The southern escarpment is less precipitous, but yet 

 readily mapped. The greatest altitudes are attained in the north 

 where the Simien Mountains tower over 15,000 feet ; the lowest alti- 

 tudes are in the south where the hills of Sidamo and southern Shoa 

 come to only a little over 4,000 feet. (PI. 4.) 



The mountainous masses in this area appear to be largely older than 

 the Rift Valley, whereas in Kenya Colony and Tanganyika Terri- 

 tory the high, more or less isolated peaks are younger than the Rift 

 Valley, the faulting of which is, indeed, looked upon as one of the 

 precipitating causes of their formation.*' The parts of the Rift Val- 

 ley studied in the field by Gregory, Willis, and other investigators 

 have been farther to the south — in Kenya Colony, Tanganyika Ter- 

 ritory, and along the eastern border of the Belgian Congo, but the 

 relatively few geologists who have made observations in Ethiopia 

 seem convinced that the Rift cut the previously elevated highlands of 

 Mesozoic age, and that the subsidence and inundation by lava of the 

 Red Sea border land were contemporaneous with it. The valley of 

 the Hawash River, which forms part of the Rift Valley, may serve 



* See J. W. Gregory's excellent book, "The Great Rift Valley", 1896. 



