337 



the alleged age of the strata ; and he cannot think this formation 

 an exception to the general law of deposit. Mere mineralogical 

 qualities should not outweigh the geological evidence in favor of 

 a more recent formation ; he cannot admit here so remarkable 

 an exception as is implied in the hypothesis that the age of these 

 sandstones may indicate the existence of birds at an earlier period 

 than geology has fixed by the regular succession of fossil 

 remains. 



Dr. Jackson replied, that his remarks were thrown out rather 

 as hints to excite inquiry than as assertions upon which he was 

 very positive ; amid the discrepancy of authors, he merely men- 

 tioned certain facts in his possession which he thought might 

 throw some light on this obscure subject. 



He said he was happy to hear Prof. Agassiz's opinions upon 

 this subject, but he regretted that he had not heard his full 

 statement at the last meeting. Prof. Agassiz misapprehended 

 some points which were not given by Dr. Jackson as results 

 but were proposed as questions for consideration. He does not 

 wish to be understood as affirming that bird tracks are found as 

 low as the Silurian system, but asked if the strata in which 

 they are found may not be older than the new red Sandstone of 

 Europe. As to the beds containing fossil fishes, he understood 

 Mr. Wells to say, that they occupied upper and unconformable 

 strata of fine-grained shales or slates resting upon the more 

 highly inclined red Sandstones of the Connecticut River. This 

 fact he had also learned from others who had examined the fish 

 deposits lower down the river, and he had no doubt of the cor- 

 rectness of Mr. Wells's opinion, that the fossil fishes belong to 

 more recent and upper beds. He understood from Mr. Redfield 

 that he did not regard the fishes of the New Jersey Sandstone as 

 identical with those of the new Red of Europe, and such was 

 the general opinion of those familiar with the deposits. 



In his communication at the last meeting. Dr. Jackson stated 

 the facts that he positively knew, distinct from matters of 

 opinion, and explained the true position of the red Sandstone 

 rocks from Lake Superior to Nova Scotia. He then repeated 

 his demonstrations, showing that the red Sandstone of the Con- 

 necticut River rests directly upon the granitic rocks of North- 



PROCEEDINGS B. S. N. H. 22 DECEMBER, 1850. 



