UPPER CRETACEOUS. 639 



Page. 



J-K 13-14 Eastern Colorado, Kansas, and Nebraska 672 



K 12 Northeastern Utah, northwestern Colorado, and southwestern Wyoming 673 



K 13 Northern Colorado and Wyoming 678 



K 14-15 Iowa and Minnesota 682 



K 18 Long Island 682 



K 19 Massachusetts (not mapped) 682 



K-L 12-13 Northern Wyoming 684 



K-L 13 South Dakota and northwestern Nebraska 685 



L 10 Western Washington 685 



L 10-11 John Day Basin, Oregon. (See Chapter XIV, p. 621.) 



L 12-13 Eastern Idaho, northwestern Wyoming, and Montana 685 



L 13-14 South and North Dakota .' 691 



M 9-10 Vancouver Island 692 



M 11 Canadian Rockies, Alberta and British Columbia (not mapped) 693 



M 12 Northwestern Montana 694 



M-N 11-14 Plains of Alberta, Saskatchewan, and Manitoba 695 



4-5 Alaska Peninsula (mapped with Jurassic) 698 



8 Southeastern Alaska. (Mapped with Lower Cretaceous. See Chapter XIV, 



pp. 632-633.) 



O 10-12 Northern British Columbia and Alberta 698 



P 8 Lewes River, Yukon Province , 700 



P-Q 4 Lower Yukon, Alaska 701 



Q 7 Upper Yukon, Alaska (not mapped) 703 



Q 8 Northern Yukon Territory 703 



Q-R 8-10 Mackenzie basin 703 



R 5 Northern Alaska, Arctic slope; (See Chapter XIV, p. 636.) 



R 22 West coast of Greenland 704 



D 19. CtTKACAO, AE.UBA, AND BONAIBE. 



The little islands of Curacao, Aruba, and Bonaire, in the Dutch West Indies, were 

 mapped by Martin.^^^ He identified the Upper Cretaceous (Rudistenkalk), which 

 on Curacao consists of a fine-grained crystalline limestone, of dirty blue or yeUow- 

 white color, that resembles a Paleozoic rock. The strata are rich, however, in 

 remains of Rvdistes radialites Lam., which are identified by Stanton on the basis 

 of Martin's illustrations as of Upper Cretaceous age. There is also a siliceous slate 

 formation with which the limestone occurs in immediate and conformable contact. 



E 18. JAMAICA. 



HiU's work on the geology of Jamaica "'* is the basis of the mapping of that 

 island and affords the following excerpts. Many details of the original work are 

 necessarily omitted. Hill classifies the geologic formations of Jamaica into four 

 great categories, as follows: 



1. A fundamental series of stratified shales and conglomerates (of terrigenous origin), 

 tuffs and other debris of volcanic material (whose source is not apparent), and, rarely, marine 

 limestones and marls, all of which have suffered great displacement and deformation. This 

 series characterizes the higher mountains and forms the nucleus of the island structure upon 

 or around which aU subsequent formations have accumulated. 



2. A series of organically derived oceanic material — marls and limestones — which rest 

 unconformably against and upon but do not completely overlap the more elevated outcrops 

 of the first-mentioned series. It constitutes piedmontal formations of great thickness around 

 bases of the higher mountain summits. 



3. Laccoliths, dikes, and siUs of igneous rocks, which penetrate the first series and the 

 lower portion of the second and are, therefore, of later age than both. 



4. Certain deposits of alluvium, oceanic marls, and coral reef rock, which are adjacent to 

 the present coasts and represent fringing reefs and other accretions around the island's border 

 after it had almost attained its present area and outline. 



