626 GEOLOGY 



strata of this field appear to dip gently 



toward the center of the basin (i. e.. tmvnrd 



i5oo Egg 2^^ 1 the center of the Lower Peninsula). The 

 Jsii 2 formations of this basin were probably 

 e 14 B ^cpi never connected with those of the other 



P| S6'B I coal-fields. 



1300 E3 I cfeLs (4) The Eastern Interior field covers 



8^- an area of about 58,000 square miles in 

 1200 jHij o IHJ Indiana, Illinois, and Kentucky (Fig. 

 ^ g oT 438), and about 55 per cent of it is pro- 

 J^ ductive. This field is set off from the 

 Appalachian field on the east, and from 

 the Western Interior field on the west, by 



1000 [_LJ '-B-^To broad low anticlines from which the Coal 

 Measures, if ever present, have been 

 eroded. It is probable that this field 



P "3^'o was once connected with the next, and 

 - glggl , l t ~ HH^ Qj 



soofiH -^ d"^ perhaps with the Appalachian field. 



|tl S (5) The Western Interior and South- 



$ s^ o ^3 



^-S_r western fields constitute a nearly contin- 



.*? 8 uous area of Coal Measures formations, 



^d g "a stretching from northern Iowa to central 



l^tiJ: g Texas, a distance of 800 miles, and cover- 



g6.2 ^ m S an area ^ 94,000 square miles. On 



^ "<3J25 the east this field is limited by the broad 



O o *"^ 



-S^x: "3 ^ ow anticline which borders the Kastern 



S^iS^ Interior field on the west. It is limited >n 



= 4<) @ c -^^ ^ ne wes ^ by the overlap of younger forma- 



^ tions. Except in Arkansas and Oklahoma. 



:',oo^^ g.2 2^^ , where the strata are folded, the bed- 



Measures of this area are e 



, (J otej l^^l^ tially horizontal. 

 * Rl s-^^.S East of the Appalachians. 77/. 



ra T 83^ Scotian-New Brunswick coal-Ji<I<l lies on 

 either side of the Bay of Fundy and 



^^ contains an area estimated at about 



18,000 square miles. The coal is l.itu- 



