\ 



Geological Society. 147 



Remarks on the Trap Rocks of Fife," by the Rev. John Fleming, 

 D.D., and communicated by Charles Lyell, Esq., V.P.G.S. 



The trap rocks of Fifeshire are referred by Dr. Fleming to three 

 distinct epochs of volcanic action ; and he says that the products of 

 each epoch are not more decidedly characterized by dissimilarity in 

 their relationship to the associated sedimentary rocks than by dif- 

 ferences in their composition. 



The traps of the first epoch occupy the northern portion of the 

 county from Stratheden to the estuary of the Tay, constituting the 

 eastern extremity of the Ochils. They appear to be coeval with the 

 grey sandstone (Arbroath pavement), and to rest upon, as well as to 

 be variously associated with the old red sandstone, and to be covered 

 by the yellow sandstone which supports the mountain limestone. 

 Viewed on a great scale, they consist of amygdaloids containing ir- 

 regular masses of porphyry, clay-stone, clink-stone, compact felspar, 

 green-stone, and trap tuff: they also contain thin layers of slate- 

 clay and grey sandstone. The whole of the igneous rocks are de- 

 cidedly stratified ; and though the beds are thick and variously bent, 

 they have, in general, the same dip as the superior and inferior sedi- 

 mentar)'^ formations. The materials of which they are composed. 

 Dr. Fleming conceives were spread out under water, partly as lava 

 and partly as ashes ; and that several of the peculiarities of rocky 

 structure have been produced by corpuscular action. 



Two vertical greenstone veins traverse this group in an easterly 

 direction. One of them may be traced along the north side of the 

 Ochils from the neighbourhood of Newburgh by Norman's Law to 

 Luthrie, a distance of nearly six miles : the other, observable at 

 Alva and DoUard, on the south side of the Ochils, may be traced 

 nearly forty miles by Monymeal to Hilton Bridge, north of Cupar. 

 Several cross veins of greenstone and felspar likewise occur. 



The trap rocks of the second epoch form the southern margin of 

 Stratheden, and may be considered as constituting a ridge parallel 

 with the Ochils, from near St. Andrews to StirHng ; but several 

 branches or patches of the same age have been observed in the 

 counties on the south of the Forth. These traps consist almost ex- 

 clusively of greenstone, which in a few instances is earthy and 

 amygdaloidal. They cover, in many places, the lower beds of the 

 coal-measures ; on the East Lomond they are intermixed with the 

 mountain limestone ; and at Wemyss Hall Hill, south of Cupar, they 

 overlap the limestone, and are in contact with the yellow sandstone. 



ITiese two groups of trap rocks, the author is of opinion, were 

 produced while the associated strata of old red sandstone and coal- 

 measures were horizontal ; and that they have undergone, equally 

 with the sedimentary formations, the movements which gave the 

 strata of the Ochils and the ridge south of Stratheden the southerly 

 dip. He is also of opinion, that the greenstone of the second group 

 may have furnished materials for the great veins, which traverse the 

 older one. 



The traps of the third epoch occur chiefly along the shores of the 

 Forth, and in the higher coal-measures. They consist of basalt with 



l2 



