113 



the current, but varies considerably on each side of it, was to 

 give rise to complicated, deltoid deposits. Hence, to ascertain 

 the true line of the current, it is necessary to take the mean of 

 numerous observations. By applying these principles to the 

 study of the oolitic sandstone of the Yorkshire coast, the author 

 found that the drift bedding indicated that the currents had 

 been from points varying from E.N.E. to W.N.W., the mean 

 being from N.N.W. to N.W. The direction indicated by the 

 ripple marks varied from N.E. by E. to N.W. by W., the mean 

 being from N. to N.N.W. Whence the mean derived from 

 these two sources combined is N.N.W. Now, unless this 

 direction of drifting be due to some interference of currents, 

 a point which the author had not investigated, we must, he 

 thought, look N.N.W. for the land on which the plants grew 

 which are now found fossil in the sandstone and shales ; and if 

 we do so, the first we come to is that part of Scotland near 

 Aberdeen. This however, he considered, was much too remote 

 to account for the fact of ferns being found fossil with the 

 spores still in the thecse, or for the deposits containing only fresh 

 water remains ; and therefore that we are compelled to admit — 

 that at the period of the deposition of the rocks containing 

 them — a tract of land existed, which has since been permanently 

 submerged. This tract was probably composed of igneous and 

 metamorphic rocks similar to those of Scandinavia ; for at the 

 base of the lower sandstones there is a deposit of pebbles com- 

 posed of rocks of that character. Hence we may suppose that 

 Scandinavia then extended considerably farther west than it 

 does now ; and that in the last movement of elevation of that 

 peninsula, this portion was, so to speak, left behind at the 

 bottom of the north sea. 



r ^ 



