1852.] 



191 



logical map, comprises in all about 50,000 square miles, nearly one half of 

 which lies in Iowa, and the other half in Missouri. From north to south this 

 coal-field is about 300 miles, and from east to west about 200. 



This coal-field is shallow, hardly exceeding fifty fathoms, and the coal-bear- 

 ing strata proper hardly 100 feet. It seems to be the attenuated part of the 

 great coal-field east of the Mississippi. It contains from four to six workable 

 beds of coal, which, in Iowa, vary from two to five or five and a half feet. 

 Towards the southern margin of tbis coal-field, in Missouri, there are beds of 

 great thickness 20 feet or more of a character intermediate between cannel 

 coal and asphaltum. 



The coal of this coal-field is all highly bituminous and most slaty in its struc- 

 ture ; very frequently presenting the woody fibre on the surface of the natural 

 joints as distinctly displayed as on charcoal. 



On the extreme south of this map will be observed, close to the southern 

 margin of this coal-field, an uplift of magnesian limestone and sandstone of 

 lower Silurian date, bordering on the lead region of Missouri, and to be found on 

 both sides of the Missouri river, between Tavern Rock and Marion ; here the 

 carboniferous and lower Silurian rocks, are in close proximity and much 

 blended together. 



To the extreme west of the map, on the Missouri river, opposite the mouth of 

 Floyd's river, the green represents the cretaceous formation which extends 

 west of the Missouri river towards the heads of the Cheynne, ilcreau and 

 White rivers, where it is succeeded by that remarkable Eocene tertiary basin 

 in the Mauvaise Terres of Nebraska, containing those interesting extinct races 

 of fossil mammalia described by Dr. Leidy in the Memoir forming part of the 

 geological report. 



Many important additions will be found to our geographical knowledge of the 

 country, derived partly from drafts and astronomical observations made by th 

 geological corps, and partly from the most recent linial surveys. 



For further particulars I beg to refer the members to the forthcoming geolo- 

 gical report of the surveys of the region of country represented by this geolo- 

 gical map. 



November 16^A. 

 Vice-President Bridges in the Chair. 



A note was read from Mr. Elias Durand, dated Nov. 15, 1852, accom- 

 panying his donation, acknowledged this evening, of 109 autographs of 

 Scientific and Literary men. 



Dr. B. H. Coates stated that he had been referred by a friend to a passage ia 

 page 136, of a work entitled "The Unity of the Human Races, proved to be the 

 doctrine of Scripture, Reason and Science ; by the Rev. Thomas Smyth, D. D. 

 New York, 1850" in which his name is cited, with those of several others, as 

 that of an "opponent" of the doctrine or dogma of the Unity of the Human 

 Species ; and this on the authority of the late Dr. Morton. Dr. Coates had no re- 

 collection of the passage in any of the writings of his late honored friend just named, 

 or of any other, in which such a statement had been made for him ; and could only 

 presume that Dr. Smyth has either misapprehended some expression in Dr. 

 Morton's books, or has quoted from memory without referring to the text. Dr. 

 Coates hoped to be allowed to have placed upon record in the Proceedings of the 

 Academy an explicit denial of the above allegation, having never held the opinion 

 there implied as his. He acquiesces in what he believes to be the general 

 judgment of the most scientific men the unity of the human species without 

 claiming to have formed an independent opinion; but he is not ignorant that 

 some strangely marked varieties, as the Ethiopian, are of a very high antiquity. 



The proposition frequently combined with the above, that the origin of the 



