1E4 Ona remarkable Stratum of Limestone, [J apt. 



Feet. Incheii. 



Intercepted stratum of quartz. 



Marly schistus, intermediate in colour between 

 greenish-grey and yellowish-grey, and con- 

 taining the charred remains of vee;etables, 10 



Coal. r \i 



Bituminous shale 2 



Bituminous shale, differing from the preceding 



in being filled with nodules of ironstone ..11 1 



Limestone. 



Schistus containing petrified entrochi, but no 



ironstone nodules 4J- 



Lime of considerable thickness, and wrought 

 for the purposes of sale. 



These strata are laid open to view on the side of a steep bank 

 overhanging the stream of the Calder, on Mr. Young's property 

 of Calder Side ; and a short distance further up the stream thaa 

 Calder Wood, the seat of Sir W. Maxwell. 



The stratum o{ perforated limestone is the phenomenon which 

 here attracts the notice of the naturalist. A representation of 

 its appearance, as seen at Calder Side, is attempted in the 

 sketch of the section of the strata (PI. 1.) mentioned in the 

 table, and I shall request your indulgence in my endeavours 

 now to describe it at somewhat greater length. 



To account in a satisfactory manner for the formation of any 

 stratum, or to explain the causes which have produced the most 

 common geological appearances, are, perhaps, equally beyond 

 the power of human talent, as to account for the formation of 

 the perforated stratum of Calder Side. For these reasons I 

 shall endeavour to confine myself to a mere description of the 

 appearance of this stratum, and avoid any speculations as to its 

 origin. It must be owned at the same time that while the 

 common occurrence of many wonderful and inexplicable geolo- 

 gical phenomena divest them in our eyes of the remarkable 

 features which they in reality possess, that the imagination is 

 almost irresistibly set at work, when so singular an appearance 

 presents itself, as the one now under consideration. 



This stratum probably consists of millions of blocks resem- 

 bling those figured at fig. 2, for a great part of it is still covered, 

 by the superincumbent strata of schistus, &c. When observed , 

 in their natural positipil, these blocks are placed on end, their 

 upper and lower ends forming the upper and under superficies of 

 the stratum, which is here nearly in a horizontal position, and 

 when first exposed by the removalof the superincumbent strata has 

 the appearance of a pavement similar to some parts of the Giant's 

 Causeway, from the ends of the blocks being so exactly fitted, 

 and dovetailed into each other. This pavement is, however, 

 hollow, and a labyrinth of concealed apartments exists in its 

 interior, for the blocks which at their extremities are nicely fitted 



