PEOF. T. ETTTERT JONES — OX COAL. 95 



Henry De la Bcche. To him we are indebted for the approximate 

 demarcation of the bounds and niar<;ins of the Carboniferous 

 formations, partiouhirly ftu" the probable huid-limits and outward 

 extension of the Coal-measures. In his valuable memoir "On the 

 possible Extension of the Coal-measures," * he explained the reasons 

 for his indicating: on the map then communicated to the Geolo<;ical 

 Society, the physical configuration of North-western Europe at the 

 close of the Paheozoic Period, and the outline of the surfaces which 

 supported the coal -vegetation. He concluded to define the place 

 and range of this old coal-growth in what is now Western Europe 

 as " an internal sea, around and occasionally over large parts of 

 which the peculiar vegetation of the time was developed and 

 entombed as the area rose and sank. A region with a central 

 depressed area, such as Australia is supposed to present, and going 

 down, by means of a long series of oscillations, would ultimately 

 present just such an assemblage of deposits as our own Carboni- 

 ferous group." 



A further reference to this kind of level or hollow region is as 

 follows: — "The large level tracts which lie west of the Blue 

 Mountains in Australia, into which the Lachlan, the Darling, the 

 Murrumbidgee, and the Darling discharge." (Godwin-Austen's 

 Lecture, Royal Institution of Great Britain, April 16, 1858.) 



Such an area had also been indicated in 1846 by Sir H. De la 

 Beche in his memoir " On the Eonnation of the Rocks of South 

 Wales and South-western England," f where he refers to "the 

 great area extending from the country drained by the Volga, 

 eastward through eightv degrees of longitude into China, and from 

 which the waters find no course outwards to the main ocean or to 

 the seas connected with it." With a gradual depression — with 

 the detritus swept in by the rivers — and with a suitable flora and 

 climate, there might here be both extensive accumulations of 

 vegetable matter grown in place, as well as limited deposits of 

 drifted plants; under different conditions. De la Beche, more- 

 over, referred to the long flat coast of the eastern seaboard of 

 South America, with its great rivers and abundant flora, as being 

 analogous to some parts, at least, of the areas on which the coal- 

 seams were formed. 



The area of coal-growth in this jS'orth- western European region 

 is represented on Mr. E,. A. C. Godwin- Austen's map | as a littoral 

 belt (varying in width as now exposed at the surface), reaching, in 

 an approximately semicircular or bay-like shape, fi'om the Elbe 

 near Magdeburg, and north of the Hartz, westward to the valley 

 of the Ruhr, including a southern extension to Marburg; and, taken 

 up again, passing from the Ruhr to Aix-la-Chapelle, and to 

 Namur and Charleroi ; thence by the Eranco-Belgian coal-field to 



* 'Quart. Joum. Geol. Soc.,' vol. xii, 1856, pp. 38-73; see also 'Coal 

 Commis.sion Report,' 1871, pp. 424 and oil, with plates; aud 'Hep. Brit. 

 Assoc.' for 1879, p. 227, plate xiv. 



t ' Mem. Geol. Survey Gt. Brit, etc.,' vol. i., p. 296. 



i ' Quart. Joum. Geol. Soc.,' vol. xii, 1856, plate i. 



