Septejiber 6, 1895.] 



SCIENCE. 



279 



nellsville, 1200 A. T. 7. A broad stream 

 to westward over flat country north of 

 Portage. 8. Warren Water. 9. Lake Iro- 

 quois. 10. Present relations. The speaker 

 also described the terraces, bisected deltas 

 and other surface deposits that corresponded 

 to the several cols, and remarked that there 

 were but four places where the present 

 streams were working on rock. 



I. C. White asked if the old burned chan- 

 nels around these rock cuts were known, 

 but the speaker replied that there was too 

 much drift and too few borings. President 

 Shaler argued that the cols of the first stage 

 were due to subglacial streams. J. W. 

 Spencer, W. M. Davis and H. S. Williams 

 brought up minor points, after which ad- 

 journment was made for lunch. 



The Society met at 2 and listened to an 

 extended paper by Professor B. K. Emerson, 

 of Amherst, on ' The Geology of Hamj)shire, 

 Hampden and Franklin Counties, Mass.' 

 These are the three counties along the Con- 

 necticut river in Massachusetts. They 

 embrace Archean crystalline rocks, meta- 

 morphosed Cambrian and Devonian sedi- 

 ments, Triassic sandstones and traps. 

 Glacial deposits and Champlain clays. The 

 speaker illustrated his remarks by large 

 maps, the results of nearly twentj^-five 

 years of study. His address was divided 

 into three heads. He first took up the 

 Archean and paleozoic rocks. The former 

 are in the continuation of the Green Moun- 

 tains and lie on the west side of the valley. 

 Among other things they embrace a great 

 belt of granite containing inclusions of mar- 

 ble, and a great belt of hornblende schist on 

 which rests the emery bed at Chester. On 

 the older crystallines lies unconformably the 

 Cambrian conglomerate now metamor- 

 phosed to gneiss, and the same appears at 

 Monson on the east, where it is quarried 

 as granite. The Devonian beds appear at 

 Bernardston and exhibit remarkable con- 

 tact metamorphism. The second part of 



the paper dealt with the Triassic sandstones 

 and traps. The dikes, plugs, tuffs, and the 

 faults characteristic of this series were de- 

 scribed. The third part of the paper dis- 

 cussed the glacial deposits, Champlain clays 

 and the variations in the channel of the 

 Connecticut river in the formation of ox- 

 bows. 



The address was the most imj)ortant of 

 the meeting and was listened to with close 

 attention by all. present. 



The next paper was by W. B. Clark, of 

 Baltimore, ' On the Eocene Fauna of the 

 Middle Atlantic Slope.' The speaker re- 

 viewed our previous knowledge of the forms 

 of life of this period and detailed the great 

 increase in the number of species and in the 

 sharpness of their determination that had 

 resulted from the explorations of the last 

 few years. The faunas were now so well 

 understood and established as to be of great 

 stratigraphic value. The paper was fol- 

 lowed by R. T. Jackson and T. A. Jaggar, 

 of Cambridge, Mass., on the ' Ai-rangement 

 and Development of Plates in the Meloni- 

 tidse.' The anatomical structure and life 

 history of this group of echinoderms were 

 described. • The next paper was by Wm. H. 

 Hobbs, Madison, Wis., ' Pre-Cambrian Vol- 

 canoes in Southern Wisconsin.' The 

 speaker presented a preliminary report on 

 the study of a group of isolated areas of ig- 

 neous rocks which protrude through the 

 Potsdam sandstone in the valley of the Fox 

 river, Wisconsin. Some of these areas rep- 

 resent local outflows of rhj'olitic lava which 

 exhibits superb examples of spherulitie, 

 perlitic, fluxion and breccia structures. 

 The originally glassy ground mass of these 

 rocks has become devitrified ; hence they 

 are apo-rhj^olites, and they have been sub- 

 jected to dynamic metamorphism and sub- 

 sequent infiltration of silica. They are in- 

 truded by dikes of both basic and acid rocks. 

 Specimens and photographs of sections were 

 exhibited. 



