460 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



material interposed between them ; the pans being adapted to 

 be used singly in the ordinary way, or attached together to form a 

 baker — which, when filled with the article to be baked, is buriedf 

 in hot ashes, or placed in an open fire, and the article cooked in 

 an expeditions manner. 



The Chairman had found the quality of the cooking good. A 

 question now arose whether this pan would be liable to become 

 warped in use, and also whether the non-conducting material 

 might not be a serious inconvenience in using a fire of green 

 wood. 



Mr. Butler suggested that the former doubt might be removed 

 by causing the two pans, with the fire-proof filling, to lap over 

 somewhat ; and expressed the opinion that there would be no 

 difficulty from the latter cause. There would soon be a bed of 

 coals and heat sufficient for cooking. 



AMERICAN GEOLOGY. 



Dr. Stevens resumed : The subject this evening is what is 

 known as the mammalian era, or the age in which mammals 

 first appeared in large numbers, and were the highest type of 

 animals known upon the face of our continent. During this era, 

 it appears that Lake Michigan, and all the waters of the north, 

 had an outflow southwards ; and were, also, connected with 

 Lake Winnepeg and Hudson's Bay on the north. The communi- 

 cations between the lakes and the Ohio and Mississippi rivers 

 left large islands in the northwestern States. Across the 

 continent from the Connecticut river to Wisconsin, ancient 

 sea beaches still remain, and are found sometimes in the 

 mountains and sometimes in the valleys, at different eleva- 

 tions, some more than six hundred feet above the present 

 level of the ocean, showing that there were several stages in 

 the elevation of the American Continent, the continent re- 

 maining stationery at each epoch long enough for sea beaches 

 to be formed. In Canada, and in some places in the United 

 States, sea shells, and the teeth of whales, walruses, seals, and 

 other marine animals have been found in these ancient sea 

 beaches. At Poughkeepsie, in the valley of the North river, the 

 teeth, bones, and horns of the great Northern deer, now never 

 found in latitudes lower than Labrador, have been found buried 

 in. the sands of the tertiary or mammalian era. In Rhode 



