140 Association of American Geologists and Naturalisls. 



The lattei" spoke of the ten'aces of the St Lawrence and the Lakes. 

 Some of them give evidence that they had been formed by drainings 

 of the upper lakes. 



Prof. J. W. Bailey read a paper upon the structure of anthracite 

 coal. He found the evidence of the leaves, &c., in the coal. Thin 

 slices of coal shewed very plainly the vegetable tissue. But there 

 was no evidence that arborescent plants had entered into the forma- 

 tion of coal, it was only the deciduous and soft portions which had 

 been converted into coal. Anthracite coal had alone been examined ; 

 soft coal containing so large a quantity of bitumen could not so 

 readily be tested. 



A few remarks passed between Professor Bailey and Mr Tesch- 

 macher, upon an apparent discrepancy in their views in relation to 

 the subject of coal. 



Professor Hitchcock read a paper, being an attempt to discrimi- 

 nate the animals which had made the fossil footmarks in the Con- 

 necticut valley. He had discovered forty-seven species in nineteen 

 localities. At some length, he argued the propriety of his giving 

 names to the birds as well as to the footprints. He then stated the 

 peculiar characteristics of the footmarks which led him to assign the 

 names that he had done, to the birds — such as thick and narrow 

 toes, winged feet, number of toes, absolute and relative length of 

 toe, spread of lateral toes, projection of middle toe beyond the lateral 

 ones, distance between the tips of the lateral toos, distance between 

 the tips of middle and outer toes, direction of hind toe, character of 

 the claw, width of toe, number and length of the phalanges, the im- 

 pression on the mud, length of step, distance of feet from line of 

 direction, &c. The number of toes varies from three to five. 



He explained the means by which to distinguish between the 

 marks of quadrupeds and bipeds, described the classes into wliich ho 

 had divided the birds, and pointed out their affinities. In one spe- 

 cimen which he had found, every alternate step was turned at an 

 angle of 45 degrees from the line of direction. He could explain 

 this only by the conjecture that the animal had broken its leg, and 

 for want of good medical advice the leg was set awry, and this was 

 the cause of the very singular footmark left on the rock. Some 

 giant footsteps, twenty inches in length, he believed to be those of 

 frogs. They resembled closely in character the embryo foot of a 

 frog which had been shewn to him by Professor Agassiz, and here 

 he would remark that the fossils discovered more generally resemble 

 the embryo of animals of the present day than adults. 



Wednesday Afternoon. 



Professor Horsford, of Harvard University, read a paper, shew- 

 ing that Barium, Strontium, Lime, and Magnesia, and their salts, 

 are in their intensity in the order of their atomic weights. 



