74 Intelligence and Miscellaneous Articles. 



in the country described, was given, the Permian beds being in- 

 cluded, as the Author considered them the upper portion of one 

 great division of Palaeozoic time. The section was as follows, with 

 the maximum thickness of each subdivision : — 



Thickness in yards. 



1. Dark red Sandstone 210"] 



2. Ifton or St. Martin's Coal-measures 75 I p • 5Q0vard^ 



3. Red marls with calcareous matter 180 [ ' ^ 



4. Green rocks and Conglomerates 125 J 



5. Upper Coal-measures 80^ 



6. Cefn rock to Cefn coal 100 | n -. „„_ 



7. Cefn coal to Lower yard-coal 27 ° r ^5 S 



8. Lower yard -coal to Chwarcle coal 80 | ^ 



9. Chwarcle coal to Millstone Grit 1 35 ) 



1255 yards. 



A detailed description of the strata was next given, beginning 

 with the lowest, together with details of each coal-seam as worked 

 in various parts of the field. After describing the beds from the 

 Millstone Grit to the Cefn rock in the North- Wales coal-field, the 

 Author proceeded to notice the Upper Coal-measures and Permian 

 strata in the Shrewsbury area, and showed that no break exists between 

 the two, the former passing gradually into the latter. He then 

 discussed the probability of Lower Coal-measures existing beneath 

 the upper beds near Shrewsbury, and showed from sections that the 

 existence of the lower measures might be anticipated. A similar 

 inquiry as to the presence of the Coal-measures beneath the New 

 Eed Sandstone of the Yale of Clwyd should also, in the Author's 

 opinion, be answered in the affirmative. 



The organic remains found in the different beds were briefly 

 noticed, and then the faults of the district were discussed at some 

 length. The principal faults run north and south, with an upthrow 

 to the east, but are crossed by lines of fracture running east and 

 west. 



In conclusion, the correlation of the strata in the North Wales 

 and Shrewsbury coal-fields, and especially of the coal-seams, with 

 the beds found in other parts of Great Britain, was discussed, and 

 a section was given to show the representation of the different 

 measures in various coal-basins. The Author was disposed to adopt 

 four subdivisions rather than three only, as usually accepted, and 

 pointed out some of the characteristics of each subdivision. 



XII. Intelligence and Miscellaneous Articles. 



ON THE DEPTH TO WHICH DAYLIGHT PENTRATES IN SEA- 

 WATER. BY MM. H. FOL AND ED. SARASIN. 



TN a previous paper * we gave an account of some experiments 

 -*- which we had made in the Lake of Geneva, with a view to de- 

 termine the limit of penetration of sunlight in water, and we 

 announced our intention of making similar experiments in the sea. 

 * Phil. Mag. January 1885, p. 70. 



