Cn. XXXII] 



CARBONIFEROUS VOLCANIC ROCKS. 



697 



Forth in Scotland. The newest of these, connected with the higher 

 series of coal-measures, is well exhibited along the shores of the 

 Forth, in Fifeshire, where they consist of basalt with olivine, amyg- 

 daloid, greenstone, wacke, and tuff. They appear to have been 

 erupted while the sedimentary strata were in a horizontal position, 

 and to have suffered the same dislocations which those strata have 

 subsequently undergone. In the volcanic tuffs of this age are found 

 not only fragments of limestone, shale, flinty slate, and sandstone, but 

 also pieces of coal. 



Fig. 731. 



Eock and Spindle, St. Andrew's, as seen in 1838. 

 a. Unstratified tuff. &. Columnar greenstone. c. Stratified tuff. 



. 



