MESOZOIC PLANTS FllOM KOREA. 3 



Tlie development of this Kyöng-syang formation is princi- 

 pally found in a rectangular area bounded on the east and south 

 by the coasts of Kyöng-syang-Do, on the west by the meridian 

 of 128° and on the north by a line roughly coinciding with 

 lalitude 36° 30'. The region covers the main portion of the well 

 populated Kyöng-syang-Do, with exclusions of numerous small 

 areas composed of Tertiary and younger sediments, and also of 

 eruptives. 



There is another area in which this formation is found, but 

 it is less extensive, lying in southern Chyol-la-Do. Like the 

 other it is almost quadrate in outline, being bounded by the lines 

 connecting Mokplio, Ok-koa, Ku-ryoi and Hai-nam successively, 

 and is composed of two topographically well marked portions, the 

 low, well cultivated southwestern plain and the more or less wooded 

 northeastern highland. 



Connecting these two separate areas, there runs a narrow 

 belt of the same sediments, from northeast to southwest for about 

 200 km. through Chyol-la-Do. From Mokpho in the southwest, 

 it runs through Chyang-syong and then north of Im-sil, west 

 and north of Chin-an and near Mu-jyu where it disappears for a 

 short distance in a region consisting of gneisses and biotite-schists. 

 But it reaj^pears at the southwest of Yong-dong in Chhung- 

 chhyöng-Do which lies due north of Hoang-gan. It is again 

 intercepted by the gneiss plain of Syang-jyu for a distance of 

 about 20 km. In general, the belt has a width of about 16 km. 

 along the road between Ok-chhyön and Hoang-gan, and between 

 Im-sil and Chyöng-jyu. 



East of Chhyön-san, in Chhyung-chhyöng-Do, there is also 

 an isolated area composed of the same rocks, but its exact extent 

 is at present not definitely known. 



