54 



COMMENCEMENT OF LAND ANIMALS. 



The plants of this era are few and unobtrusive. Equ* 

 seta, catamites, ferns, Voltzia, and a few of the other fa- 

 milies found so abundantly in the preceding formation, 

 here present themselves, but in diminished size and quan- 

 tity. 



This seems to be the proper place to advert to certain 

 memorials of a peculiar and unexpected character respect- . 

 ing these early ages in the sandstones. So low as the 

 bottom of the carboniferous system, slabs are found mark- 

 ed over a great extent of surfaces with that peculiar cor- 

 rugation or wrinkling w r hich the receding tide leaves upon 

 a sandy beach when the sea is but slightly agitated ; and 

 not only are these ripple marks, as they are called, found 

 on the surfaces, but casts of them are found on the under 

 sides of slabs lying above. The phenomena suggests the 

 time when the sand ultimately formed in these stone slabs, 

 was part of the beach of a sea of the carbonigenous era ; 

 when, left wavy by one tide, it was covered over with a thin 

 layer of fresh sand by the next, and so on, precisely as 

 such circumstances might be expected to take place at 

 the present day. Sandstone surfaces, ripple-marked, are 

 found throughout the subsequent formations ; in those of 

 the new red, at more than one place in England, they 

 further bear impressions of rain drops which have fallen 

 upon them — the rain, of course, of the inconceivably re- 

 mote a^e in which the sandstones were formed. In the 

 Greensill sandstone, near Shrewsbury, it has even been 

 possible to tell from what direction the shower came 

 which impressed the sandy surface, the rims of the marks 

 being somewhat raised on one side, exactly as might be 

 expected from a slanting shower falling at this day upon 

 one of our beaches. These facts have the same sort of 

 interest as the season rings of the Craigleith conifers, as 

 speaking of a parity between some of the familiar pro- 

 cesses of nature in those early ages and our own. 



In the new red sandstone, impressions still more impor- 

 tant in the inferences to which they tend, have been ob- 

 served — namely, the footmarks of various animals. In a 

 quarry of this formation, at Corncockle Muir, in Dum- 

 friesshire, where the slabs incline at an angle of thirty- 

 eight degrees, the vestiges of an animal supposed to have 

 been a tortoise, are distinctly traced up and down the 

 slope, as if the creature had had occasion to pass back- 

 wards and forwards in that direction only, possibly in its 



