ABRAHAM GESNER REVIEW OF HIS SCIENTIFIC WORK. 35 



Old Red Sandstone. 



On this map the narrow strip of measures which Dr. Gesner 

 has called old red sandstone will not easily catch the eye. The 

 "mountain limestone," which immediately overlies it, was no 

 •doubt the occasion for referring this belt of measures to the Old 

 Red Sandstone. To Dr. Gesner, if we may judge by the glossary 

 of geological terms attached to his reports, the Old Red .Sand- 

 stone was a " stratified rock belonging to the Carboniferous 

 group." This glossary is extracted from one in Lyell's Principles 

 of Geology, a book which Dr. Gesner seems to have used a great 

 deal, and in which the term Old Red Sandstone is similarly 

 defined.* It would appear that, at this time at least, the term 

 Old Red Sandstone did not convey to Dr. Gesner's mind the 

 idea of a system different from the Carlioniferous, but rather 

 that of a Lower or Sub-carboniferous Sandstone. However, some 

 years later (in 1847) he refers to the Old Red Sandstone as 

 Devonian. 



The Coal Formation. 



The compiler of this map rightly considered this system of 

 rocks as one of the most important in the province ; and he had 

 less difficulty in recognizing it than in telling the age of the 

 others. Abundant plant-remains furnished the test necessary 

 for the determination of these rocks. Though Dr. Gesner's 

 paleobotany belongs to the earliest years of geological science, 

 and some of his names are now obsolete, we are able from his 

 descriptions, and sometimes from his figures, to recognize most 

 of the plants he mentions. They are the commoner species of 

 the Carboniferous age, but sufficient to determine the kind of 

 flora which flourished in New Brunswick in those times, and 

 thus to assure Dr. Gesner that the rocks were Carboniferous. 



The limits of the coal formation, as given on this map, do 

 not differ greatly from those obtained by more recent explor- 

 ations. 



*See Lyeirs Principles, Ed. 1835, London; Vol. I, p. 396; Vol. IV, p. 313. 



