Rocks audi Fossils of Phillipshurgh, C. E. 325 



identified, indicate tlie period of the Medina sandstone and Clin- 

 ton group, regarding these two rocks as belonging to one period. 

 " It was also shown by a Fection from Lake Champlain to the 

 Green Mountains through Ferrisburgh and Monkton, that the 

 Taconic quartz rock is probably a metamorphic equivalent of 

 the above named red sandrock. In this section there is a gradual 

 chano'e in the litholoo-ical characters from the red sandrock to 

 the quartz rock ; the difference in the lithological characters, 

 however, is only such as must have been the effect of igneous 

 agency in the eastern part of the section, and the order of succession 

 of the calcareous over the quartzose members is identical in both 

 rocks. But since a small part of the section, on the opposite 

 sides of which the change of characters is most conspicuous, 

 is concealed by drift, the identity of the Taconic quartz rock 

 with the Medina sandstone was not positively affirmed. 



" A section from Buck Mountain through Waltham into New 

 Haven was exhibited, which rendered it somewhat probable that 

 the Stockbridge limestone of the Taconic system is the equiva- 

 lent of the calcareous rocks which overlie the red sandrock, 

 rather than of the lower limestones of the Champlain Division, 

 as has been commonly supposed. 



" In reply to Dr. Emmons, [an abstract of whose remarks on 

 the Taconic system we have not received,] it was stated by Prof. 

 Adams that he (Dr. E.) had misunderstood the description of 

 the calcareous rock over the Hudson river shales, which was not 

 affirmed to be the Trenton limestone, but an upper member of 

 the Hudson River shales, as proved by the contained fossils in 

 connection with the position. The remarks of Dr. E. being based 

 on this misconception of the statements actually made, could not 

 of course affect the conclusion respecting the ago of the rocks of 

 Snake mountain." Silliman^s Journal^ 2nd Series Vol. 5, p. 108. 

 The section at Snake Mountain has been, it appears, examined 

 by Prof. Hitchcock and Prof. W. B. Rogers and they have both 

 arrived at the conclusion that there is no dislocation passing 

 through the hill, as Emmonds contends, but that there is an un- 

 broken succession in conformable sequence of all the rocks of the 

 New York series, from the Trenton to the Medina inclusive. On 

 this most important section which brings Palaeontology and Physi- 

 cal Geology into a direct antagonism with each other, the follow- 

 ing are Prof. Roger's remarks, as they appear in the proceedings 

 of the Boston Natural History Society, March 7, 1860. 



