THE LAKE OF STENNIS. 



'•7 



to their town museum, to indicate to them the stratum in 

 which it had lain. It showed me, among other things, liow 



Fig. 1. 



INTERNAL RIDGE OS" HTOID PLATE OF ASTEROLEPIS.* 

 (One-third the natural size, linear.) 



unsafe it is for the geologist to base positive conclusions on 

 merely negative data. Founding on the fact that, of many 

 hundred ichthyolites of the Lower [Middle] Old Red Sand- 

 stone which I had disinterred and examined, all were of com- 

 paratively small size, while in the Upper Old Red many of 

 the ichthyolites are of great mass and bulk, I had inferred 

 that vertebrate life had been restricted to minuter forms at 

 the commencement than at the close of the system. It had 

 begun, I had ventured to state in the earlier editions of a 

 little work on the " Old Red Sandstone," with an age of 

 dwarfs, and had ended with an age of giants. And now, 

 here, unaccompanied by aught to establish the contemporary 

 existence of its dwarfs, — which appear, however, in an over- 

 Figured from a Thurso specimen, slightly different in its proportions 

 from the Stromness specimen described. 



