LECTURES. 53 



v 



here. Do not handle any specimen more than is 

 absolutely necessary, you never know to what extent 

 you have injured it. Put your jelly fishes into pails 

 of water by floating them from the net to the pail. 

 A word more about our rocks: each one must collect 

 specimens for himself. There will be found, 

 probably, upon our island, three-fourths or even 

 nine-tenths of all kinds of rocks in the United States. " 



At another time he again took up the subject and 

 said: 



"Most all of the rocks upon our island are imbed- 

 ded rocks, not rocks in place. Some of the neigh- 

 boring islands show rocks in place. Our first ques- 

 tion, upon seeing them is, Where did they come 

 from? The mineral foundation of our earth is alike 

 everywhere. This was first shown by Humboldt. 

 When you find a rock not in position, hunt for one of 

 the same kind in position, then search for specimens 

 between the two localities, and, if possible, trace 

 their connection. Loose materials are called erratic,. 

 or boulders, etc. ; the whole bulk is called drift\. 

 ledges and the like are called rocks in place. Our 

 island probably contains specimens of all of, our 

 rocks, excepting those of volcanic origin. Your 

 specimens should all be broken afresh, upon all 

 sides, so that they may be more accurately studied. 

 Rocks found near the water are usually assorted 

 (those of a size being together), the larger ones 

 lying higher up than the small ones. On hills and 

 away from the agency of water, they are mixed; the 

 small and the great lying together. By this means 

 we recognize the two agencies that are at work de- 

 positing them." 



The third lecture was devoted chiefly to hints upon 

 how to study the jelly fishes, and was illustrated by 

 numerous diagrams. Toward the end he digressed 

 from his subject to give us a few remarks upon 

 fishes, especially regarding the Scup, a specimen of 

 which, recently taken, someone had brought to him. 



