i210 Association of Geologists and J^aturalists. [Nov., 



the notice of Mr. Squiei's paper; according to this gentleman, 

 the mounds, and their contents, of the southwestern Indians, are 

 identical with those observed by him in Ohio. 



On the general results of investigations in the Paleontology of 

 the lower strata of Jfew York; hy James Hall. 



In this interesting paper many important geological results 

 were obtained, and much valuable information on the fossils of 

 America, which show that the European types can no longer be 

 made the basis of our classification of fossils. 



Mr. Agassiz observed that it is idle to draw a parallel between 

 the European and American types; those of Europe have been 

 too much disturbed by Plutonic action; America, where there is 

 not such disturbance, is by far the most favorable locality to ob- 

 serve. He w^as glad to see so good a beginning in the work of 

 establishing American fossils on a foundation independent of Eu- 

 ropean authority. 



On the depth and soilness of the Ocean, hy Com. C. Wilkes. 



There were few positive results on the actual depth of the 

 ocean; in fact, bottom has not been found in the deepest parts — 

 at any rate, 4600 fathoms had not reached it. To give an idea 

 of the difficulty of making deep sea soundings, he remarked, that 

 it took the crew of a well manned frigate, and her officers, three 

 hours to make one sounding. He concluded, from his observa- 

 tions, that the great valleys of the ocean run at right angles with 

 the great mountain chains. After alluding to different ways of 

 making these soundings, and their difficulty, he mentioned that 

 attempts had been made to obtain the depth of the ocean, by the 

 rebounding of the echo of sound produced by exploding a shell 

 under water, or at the bottom. 



He stated that the mean temperature of the ocean between 

 54 deg. and 60 deg. S. was 39.5; it has been stated by some, 

 that the minimum temperature in the Mediterranean is 55 deg. 



The penetration of solar light varied in different latitudes and 

 at different temperatures; it would naturally be supposed that the 

 depth at which a body disappears would vary between sunrise 

 and sunset, according to the obliquity of the sun's rays; but a 

 difference of only one fathom was observed. In the Gulf Stream, 

 a white body of eighteen inches diameter, disappeared at twenty- 

 seven fathoms; the depth of disappearance varies from six to 

 thirty fathoms; the disappearance is gradual. In these experi- 

 ments the eye was vertically over the object, and the observer in 

 an ordinary boat. In warm latitudes, the ship's copper could be 

 distinctly seen from the surface of the water; when in colder lat- 



