306 THE BORDERLAND OF SCIENCE. 



"been so much reduced that they would have left no 

 impressions, or only faint ones, whereas these are deep 

 and distinct. They are not unlike the impressions 

 which would be left by a small and rather plump hand. 

 It is by no means clear that this creature ever made 

 its way into the ancient forests, or could be in any 

 proper sense regarded as their inhabitant.* 



I have mentioned impressions left in sand belong- 

 ing to the carboniferous period, and the ingenious way 

 in which geologists have explained the features of these 

 impressions. There is, however, a record on the sand- 

 stone of this period, which is, perhaps, even more 

 significant. Impressions of rain-drops have been de- 

 tected in carboniferous sandstone by Dr. Dawson, Sir 

 Charles Lyell, and, more recently, by Mr. Brown, in 

 Australia ; and these rain-marks are, on the average, 

 about as large as those which are produced by the rain 

 of our own period. As Lyell well remarks, ' the great 

 humidity of the climate of the coal period had been 

 previously inferred from the number of its ferns, and 

 the continuity of its forests for hundreds of miles ; but 



* Owing to the circumstance that in our books on geology this crea- 

 ture is called a batrachian, many popular writers have been led to 

 assert that a monstrous frog inhabited the ancient forests whence the 

 vegetation pf the coal seams was derived. But the order of batrachians 

 includes other animals than the frog and toad. According to the views 

 at present adopted of the batrachian of the carboniferous period (as well 

 as of a kindred but later species called by Professor Owen the laby- 

 rinthodonf), this creature was further removed even than the newt from 

 the common frog. It probably resembled in structure creatures still 

 existing (but on a much smaller scale), which have four limbs like the 

 newt, but have gills as well as lungs. 



